Absorbent article having blood slipping agent on a top sheet thereof

ABSTRACT

An absorbent article includes a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body arranged between the top sheet and the back sheet. An excretory orifice contact area of the liquid-permeable top sheet has an area containing a blood slipping agent. The blood slipping agent has a kinematic viscosity of 0.01-80 mm 2 /s at 40° C., a water hold percentage of 0.01-4.0 mass %, and a weight average molecular weight of less than 1,000. An amount of the blood slipping agent on the clothing-side surface of the top sheet is greater than an amount of the blood slipping agent on the skin-side surface of the top sheet at a location in the area containing the blood slipping agent where the surfaces overlap in the thickness direction of the absorbent article.

RELATED APPLICATIONS

The present application is a National Phase of International ApplicationNumber PCT/JP2013/075538 filed Sep. 20, 2013 and claims priority ofJapanese Application Number 2012-218782 filed Sep. 28, 2012.

TECHNICAL FIELD

The present disclosure relates to an absorbent article.

BACKGROUND ART

As the basic performance of absorbent articles, such as sanitary napkinsand panty liners has continued to improve with technological developmentover many years, leakage after absorption of excreta, such as menstrualblood has become a less frequent occurrence than in the past, andresearch is currently ongoing with the aim of achieving even higherperformance, including a feel similar to underwear, and smoothness ofthe top sheet even after absorption of excreta, such as menstrual blood.

Menstrual blood during menstruation, in particular, can also containcomponents of the endometrium which are highly viscous, and the topsheet preferably remains smooth and stick-free even after absorption ofsuch highly viscous menstrual blood. Highly viscous menstrual bloodusually remains on the top sheet in the form of masses, generallyleaving the user with a visually unpleasant image, and therefore fromthis viewpoint as well it is preferred for no highly viscous menstrualblood to remain on the top sheet.

Absorbent articles are known in the technical field which are coatedwith lotion compositions.

For example, PTL 1 discloses an absorbent article having a polypropyleneglycol material-containing lotion composition situated on the innersurface of the top sheet (the clothing side surface), the inner surfaceof the back sheet (the body side surface), and on the base materialbetween the inner surface of the top sheet and the inner surface of theback sheet.

Also, PTL 2 discloses an absorbent article wherein a polypropyleneglycol material-containing lotion composition is applied on the outersurface of the top sheet (body side surface).

CITATION LIST Patent Literature

-   PTL 1 Japanese Unexamined Patent Publication No. 2010-518918-   PTL 2 Japanese Unexamined Patent Publication No. 2011-510801

SUMMARY OF INVENTION Technical Problem

In such an absorbent article, the lotion composition is generally coatedonto the top sheet, but the lotion composition coated onto the top sheetcan potentially cause problems, such as contamination of the absorbentarticle manufacturing line or other absorbent articles.

It is therefore an object of this disclosure to provide an absorbentarticle has a top sheet in which the excretory opening contact regionthereof has low stickiness, and is light after absorption of menstrualblood, and that does not contaminate the manufacturing line or otherabsorbent articles.

Solution to Problem

The present inventors have found an absorbent article comprising aliquid-permeable top sheet, a liquid-impermeable back sheet, and anabsorbent body between the top sheet and the back sheet, wherein theliquid-permeable top sheet has, in the excretory opening contact region,a blood slipping agent-containing region containing a blood slippingagent with a kinematic viscosity of 0.01 to 80 mm²/s at 40° C., a waterholding percentage of 0.01 to 4.0 mass % and a weight-average molecularweight of less than 1,000, and in the blood slipping agent-containingregion, the amount of blood slipping agent on the clothing side surfaceof the top sheet is greater than the amount of blood slipping agent onthe skin side surface of the top sheet at the point of overlap in thethickness direction of the absorbent article.

Advantageous Effects of Invention

The absorbent article of this disclosure has a top sheet in which theexcretory opening contact region thereof has low stickiness, and islight after absorption of menstrual blood, and does not contaminate themanufacturing line or other absorbent articles.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a front view of an absorbent article, and specifically asanitary napkin, according to an embodiment of the invention.

FIG. 2 is a cross-sectional view of the blood slipping agent-containingregion 7 of the absorbent article 1 shown in FIG. 1, along cross-sectionX-X.

FIG. 3 is a cross-sectional view of the blood slipping agent-containingregion of an absorbent article according to another embodiment of theabsorbent article of this disclosure.

FIG. 4 is a diagram schematically illustrating migration of menstrualblood into an absorbent body by a blood slipping agent.

FIG. 5 is a diagram showing the production process for an absorbentarticle according to an embodiment of this disclosure.

FIG. 6 is a diagram showing the production process for an absorbentarticle according to another embodiment of this disclosure.

FIG. 7 is an electron micrograph of the skin contact surface of a topsheet in a sanitary napkin wherein the top sheet comprises tri-C2L oilfatty acid glycerides.

FIG. 8 is a pair of photomicrographs of menstrual blood containing andnot containing a blood slipping agent.

FIG. 9 is a diagram illustrating a method of measuring surface tension.

DESCRIPTION OF EMBODIMENTS

[Definitions]

Some of the terms used in the present specification will now be defined.

“Excretory Opening Contact Region”

As used herein, “excretory opening contact region” of the top sheetmeans the region of the top sheet that contacts with the excretoryopening (labia minora, etc.) of the wearer. The excretory openingcontact region will have a different location depending on the size ofthe absorbent article, and for an absorbent article with side flaps, theexcretory opening contact region will usually be the inner side of theregion defined by embossing disposed in a continuous or discontinuousmanner surrounding a lengthwise line running through the widthwisecenter of the absorbent article, and the intersection with a widthwiseline running through the lengthwise centers of both wing sections. Also,in the case of an absorbent article without side flaps, usually theexcretory opening contact region is defined by embossing that isdisposed continuously or discontinuously surrounding the widthwisecenter section and the lengthwise center section of the absorbentarticle.

As used herein, the “second sheet” has an excretory opening contactregion. The excretory opening contact region of the second sheet is theregion overlapping with the excretory opening contact region of the topsheet in the thickness direction of the absorbent article.

“Front” and “Back”

As used herein, “front” and “back” are in reference to the wearer, andmean the front of the wearer and the back of the wearer, respectively.

“Skin Side Surface” and “Clothing Side Surface”

The “skin side surface”, as it relates to the liquid-permeable top sheetand second sheet, means the surface that faces the skin side of thewearer when the article is worn. Similarly, the “clothing side surface”means the surface that faces the clothing side of the wearer when thearticle is worn. For example, the clothing side surfaces of the topsheet and second sheet are, respectively, the surfaces of the top sheetand second sheet on the back sheet side.

Also, the skin side surface of the top sheet has the same definition as“skin contact surface”.

“Blood Slipping Agent-containing Region”

As used herein, the “blood slipping agent-containing region” as itrelates to the top sheet means the region of the top sheet containingthe blood slipping agent within the excretory opening contact region.The top sheet may have a blood slipping agent-containing region on aportion of the excretory opening contact region, or it may have theblood slipping agent-containing region across the entire excretoryopening contact region. Furthermore, the top sheet may also have theblood slipping agent-containing region in the excretory openingnon-contact region, exceeding the excretory opening contact region.

The absorbent article according to one embodiment of this disclosure hasa second sheet, the second sheet having the blood slippingagent-containing region. The “blood slipping agent-containing region” asit relates to the second sheet, means the region of the second sheetcontaining the blood slipping agent within the excretory opening contactregion, similar to the top sheet, and the second sheet may have theblood slipping agent-containing region in a portion or the entirety ofthe excretory opening contact region, while it may also have the bloodslipping agent-containing region in the excretory opening non-contactregion.

The absorbent article of this disclosure will now be explained indetail.

FIG. 1 is a front view of an absorbent article, and more specifically afront view of a sanitary napkin, according to an embodiment of thisdisclosure. FIG. 1 is as observed from the skin side surface of the topsheet 2. The absorbent article 1 shown in FIG. 1 has a liquid-permeabletop sheet 2, a liquid-impermeable back sheet (not shown), and anabsorbent body 3 between the top sheet 2 and the back sheet. In theabsorbent article 1 shown in FIG. 1, a pair of side flaps 4 are providedon both edges in the lengthwise direction of the absorbent article 1, toanchor the absorbent article 1 to the clothing of the wearer, such asshorts.

In the absorbent article 1 shown in FIG. 1, the left side is the front.

In the absorbent article 1 shown in FIG. 1, the excretory openingcontact region is the region defined by four embossings 6′ within theblood slipping agent-containing region 7, and all of the excretoryopening contact regions of the top sheet 2 have a blood slippingagent-containing region 7.

The absorbent article 1 shown in FIG. 1 has a side sheet 5 and aplurality of embossings 6, but the absorbent article according toanother embodiment of this disclosure lacks either or both a side sheetand/or embossing.

In the absorbent article shown in FIG. 1, the top sheet 2 is formed of anonwoven fabric, but in an absorbent article according to anotherembodiment of this disclosure, the top sheet is formed of a woven fabricor porous film.

In the absorbent article 1 shown in FIG. 1, at least the excretoryopening contact region of the top sheet 2 has a blood slippingagent-containing region 7 containing a blood slipping agent having akinematic viscosity of 0.01 to 80 mm²/s at 40° C., a water holdingpercentage of 0.01 to 4.0 mass % and a weight-average molecular weightof less than 1,000.

FIG. 2 is a cross-sectional view of the blood slipping agent-containingregion 7 of the absorbent article 1 shown in FIG. 1, along cross-sectionX-X. In FIG. 2, the top sheet 2, absorbent body 3 and back sheet 8 aresituated in that order from the top, and the top sheet 2 contains ablood slipping agent 9.

As shown in FIG. 2, at points of overlap (P₁ and P₂) in the thicknessdirection of the absorbent article 1 in the blood slippingagent-containing region 7, the amount of blood slipping agent 9 on theclothing side surface 11 of the top sheet 2 (the amount at P₂) isgreater than the amount of blood slipping agent 9 on the skin sidesurface 10 of the top sheet 2 (the amount at P₁).

FIG. 3 is a cross-sectional view of the blood slipping agent-containingregion of an absorbent article according to another embodiment of theabsorbent article of this disclosure. FIG. 3 corresponds tocross-section X-X of the blood slipping agent-containing region 7 of theabsorbent article 1 shown in FIG. 1. In FIG. 3, the top sheet 2, secondsheet 12, absorbent body 3 and back sheet 8 are situated in that orderfrom the top, and the top sheet 2 and second sheet 12 contain the bloodslipping agent 9.

As shown in FIG. 3, at points of overlap (P₁, P₂ and P₃) in thethickness direction of the absorbent article 1 in the blood slippingagent-containing region 7, the amount of blood slipping agent 9 on theclothing side surface 11 of the top sheet 2 (the amount at P₂) isgreater than the amount of blood slipping agent 9 on the skin sidesurface 10 of the top sheet 2 (the amount at P₁), and in the bloodslipping agent-containing region 7, the amount of blood slipping agent 9on the skin side surface 10 of the second sheet 12 (the amount at P₃) isgreater than the amount of blood slipping agent 9 on the skin sidesurface 10 of the top sheet 2 (the amount at P₁).

The absorbent article 1 according to the embodiment shown in FIG. 3includes a second sheet 12, but an absorbent article according toanother embodiment of this disclosure does not include a second sheet.

In FIG. 2 and FIG. 3, the blood slipping agent 9 is shown as droplets,but according to the absorbent article of this disclosure, the form anddistribution of the blood slipping agent is not limited to that shown inthe drawing.

Also, in the absorbent article 1 illustrated in FIG. 2 and FIG. 3, thetop sheet 2 has a blood slipping agent-containing region 7 consistingentirely of a blood slipping agent 9 in the excretory opening contactregion, but in an absorbent article according to another embodiment ofthis disclosure, the top sheet excretory opening contact region has inthe excretory opening contact region a blood slipping agent-containingregion composed of a blood slipping agent-containing compositioncontaining a blood slipping agent and at least one other component.

The blood slipping agent and the blood slipping agent-containingcomposition will now be described in detail.

In this absorbent article of this disclosure, the top sheet contains theblood slipping agent in the blood slipping agent-containing region at abasis weight in a range of preferably about 1 to about 30 g/m², morepreferably about 2 to about 20 g/m² and even more preferably about 3 toabout 10 g/m². The action of the blood slipping agent will be describedbelow, but if the basis weight is lower than about 1 g/m², menstrualblood that has reached the excretory opening contact region of the topsheet will tend to remain there without rapidly migrating into theabsorbent body, while if the basis weight is greater than about 30 g/m²,a greater degree of stickiness may be felt when the article is worn.

In the blood slipping agent-containing region of the absorbent articleof this disclosure, the amount of blood slipping agent on the clothingside surface of the top sheet is greater than the amount of bloodslipping agent on the skin side surface of the top sheet at the point ofoverlap in the thickness direction of the absorbent article, theproportion of the amount of blood slipping agent on the clothing sidesurface of the top sheet with respect to the amount of blood slippingagent on the skin side surface of the top sheet exceeding about 1.0, andbeing preferably about 1.5 or greater, more preferably about 2.0 orgreater, even more preferably about 2.5 or greater and yet morepreferably about 3.0 or greater.

If the amount of blood slipping agent on the clothing side surface ofthe top sheet is greater than the amount of blood slipping agent on theskin side surface of the top sheet at the point of overlap in thethickness direction of the absorbent article, the blood slipping agenton the skin side surface of the top sheet will not easily contact withother objects, and the blood slipping agent will not easily contaminatethe manufacturing line and other absorbent articles.

The amount of blood slipping agent on the skin side surface of the topsheet may also be 0 g/m². This is because application of pressure ontothe absorbent article when the article is worn causes the blood slippingagent on the clothing side surface of the top sheet to migrate to theskin side surface, and exhibit its effect.

In the blood slipping agent-containing region in an embodiment whereinthe absorbent article includes a second sheet, the amount of bloodslipping agent on the skin side surface of the second sheet is greaterthan the amount of blood slipping agent on the skin side surface of thetop sheet at the point of overlap in the thickness direction of theabsorbent article, the proportion of the amount of blood slipping agenton the skin side surface of the top sheet with respect to the amount ofblood slipping agent on the skin side surface of the second sheetexceeding about 1.0, and being preferably about 1.5 or greater, morepreferably about 2.0 or greater, even more preferably about 2.5 orgreater and yet more preferably about 3.0 or greater.

If the amount of blood slipping agent on the skin side surface of thesecond sheet is greater than the amount of blood slipping agent on theskin side surface of the top sheet in the blood slippingagent-containing region at the point of overlap in the thicknessdirection of the absorbent article, the blood slipping agent on the skinside surface of the top sheet will not easily contact with otherobjects, and the blood slipping agent will not easily contaminate themanufacturing line and other absorbent articles.

The amount of blood slipping agent is measured in the following manner.

The absorbent article to be measured, and grease absorbing films(product of 3M) or the like are prepared in a thermostatic chamber at40° C.

The top sheet to be measured is removed from the absorbent article andset on a platform with the clothing side surface facing upward. Eachgrease absorbing film is cut to a smaller area than the blood slippingagent-containing region of the top sheet to be measured (for example, 3cm×3 cm, 2 cm×2 cm or 1 cm×1 cm), the mass M₀ (g) of the cut greaseabsorbing films (total of 5 films) is measured, and the five greaseabsorbing sheets are stacked and placed on the blood slippingagent-containing region.

Next, a weight is set on the stack for a pressure of 30 g/cm², and after30 minutes, the grease absorbing sheets are removed and the mass M₁ (g)is measured.

The amount of blood slipping agent M_(C) (g) on the clothing sidesurface of the top sheet is calculated by the following formula:M _(C) (g)=M ₁ (g)−M ₀ (g)

A top sheet to be measured is then removed from another absorbentarticle and set on the platform with the skin side surface facingupward. A cut grease absorbing film having the same area as the amountof blood slipping agent M_(C) (g) on the clothing side surface of thetop sheet is used and the amount of blood slipping agent M_(S) (g) onthe skin side surface of the top sheet is calculated by the methoddescribed above.

The value for the amount of blood slipping agent M_(C) (g) on theclothing side surface of the top sheet is divided by the value for theamount of blood slipping agent M_(S) (g) on the skin side surface of thetop sheet, to calculate the proportion of the amount of blood slippingagent on the clothing side surface of the top sheet with respect to theamount of blood slipping agent on the skin side surface of the topsheet.

The amount (g) of blood slipping agent on the skin side surface of thesecond sheet can be measured by the method described above and theproportion of the amount of blood slipping agent on the skin sidesurface of the top sheet with respect to the amount of blood slippingagent on the skin side surface of the second sheet can be calculated.

When the sheet to be measured contains a blood slipping agent-containingcomposition, i.e. when it contains at least one other component inaddition to the blood slipping agent, the proportion can be directlycalculated by the method described above so long as different bloodslipping agent-containing compositions are not coated on the skin sidesurface of the top sheet and the clothing side surface of the top sheet,and (optionally) the skin side surface of the second sheet. This isbecause the same blood slipping agent-containing composition willcontain the blood slipping agent in the same proportion.

[Blood Slipping Agent]

In the absorbent article of this disclosure, the liquid-permeable topsheet has in the excretory opening contact region, a blood slippingagent-containing region containing a blood slipping agent having akinematic viscosity of 0.01 to 80 mm²/s at 40° C., a water holdingpercentage of 0.01 to 4.0 mass % and a weight-average molecular weightof less than 1,000.

The blood slipping agent has, at 40° C., a kinematic viscosity of about0 to about 80 mm²/s, preferably a kinematic viscosity of about 1 toabout 70 mm²/s, more preferably a kinematic viscosity of about 3 toabout 60 mm²/s, even more preferably a kinematic viscosity of about 5 toabout 50 mm²/s, and yet more preferably a kinematic viscosity of about 7to about 45 mm²/s.

The kinematic viscosity tends to be higher with a) a larger molecularweight of the blood slipping agent, b) a higher percentage of polargroups, such as carbonyl bonds (—CO—), ether bonds (—O—), carboxylgroups (—COOH) and hydroxyl groups (—OH), and c) a larger IOB.

In order to have a kinematic viscosity of about 0 to about 80 mm²/s at40° C., the melting point of the blood slipping agent is preferably 45°C. or less. This is because the kinematic viscosity will tend to behigher if the blood slipping agent contains crystals at 40° C.

As used herein, the “kinematic viscosity at 40° C.” may be referred tosimply as “kinematic viscosity”.

The significance of the kinematic viscosity of the blood slipping agentwill be explained below, but a kinematic viscosity exceeding about 80mm²/s will tend to result in high viscosity of the blood slipping agent,so that the blood slipping agent will tend to be resistant to slippinginto the absorbent article together with menstrual blood that hasreached the skin contact surface of the top sheet.

The kinematic viscosity can be measured according to JIS K 2283:2000,“5. Kinematic Viscosity Test Method”, using a Cannon-Fenske reverse-flowviscometer, at a testing temperature of 40° C.

The blood slipping agent has a water holding percentage of about 0.01 toabout 4.0 mass %, preferably it has a water holding percentage of about0.02 to about 3.5 mass %, more preferably it has a water holdingpercentage of about 0.03 to about 3.0 mass %, even more preferably ithas a water holding percentage of about 0.04 to about 2.5 mass %, andyet more preferably it has a water holding percentage of about 0.05 toabout 2.0 mass %.

As used herein, “water holding percentage” means the percentage (mass)of water that can be held by a substance, and it may be measured in thefollowing manner.

(1) A 20 mL test tube, a rubber stopper, the substance to be measuredand deionized water are allowed to stand for a day and a night in athermostatic chamber at 40° C.

(2) Into the test tube in the thermostatic chamber there are charged 5.0g of the substance to be measured and 5.0 g of deionized water.

(3) The mouth of the test tube is sealed with the rubber stopper in thethermostatic chamber, and the test tube is rotated once and allowed tostand for 5 minutes.

(4) A 3.0 g portion of the layer of the substance to be measured(usually the upper layer) is sampled into a glass dish with a diameterof 90 mm and a mass of W₀ (g), in the thermostatic chamber.

(5) The dish is heated at 105° C. for 3 hours in an oven to evaporateoff the moisture, and the mass W₁ (g) of each dish is measured.

(6) The water holding percentage is calculated by the following formula.

Water holding percentage (mass %)=100×[W₀ (g)−W₁ (g)]/3.0 (g)

The measurement is conducted three times, and the average value isrecorded.

The significance of the water holding percentage of the blood slippingagent will be explained below, but a low water holding percentage willtend to lower the affinity between the blood slipping agent andmenstrual blood, thus helping to prevent menstrual blood that hasreached the skin contact surface of the top sheet from slipping into theabsorbent article.

If the water holding percentage is high, on the other hand, affinitywith menstrual blood will be very high, similar to a surfactant, andabsorbed menstrual blood will tend to remain on the skin contact surfaceof the top sheet, resulting in more red coloration of the skin contactsurface of the top sheet.

The water holding percentage tends to be a larger value with a) asmaller molecular weight of the blood slipping agent, and b) a higherpercentage of polar groups, such as carbonyl bonds (—CO—), ether bonds(—O—), carboxyl groups (—COOH) and hydroxyl groups (—OH). This isbecause the blood slipping agent has greater hydrophilicity. The waterholding percentage will tend to have a larger value with a greater IOB,i.e with a higher inorganic value or with a lower organic value. This isbecause the blood slipping agent will have greater hydrophilicity.

The significance of the kinematic viscosity and water holding percentageof the blood slipping agent will now be explained.

FIG. 4 is a cross-sectional view corresponding to cross-section X-X ofthe blood slipping agent-containing region 7 of the absorbent article 1shown in FIG. 1, and it is a diagram schematically illustratingmigration of menstrual blood into the absorbent body by the bloodslipping agent. The absorbent article 1 shown in FIG. 4 comprises aliquid-permeable top sheet 2, a liquid-impermeable back sheet 8 and anabsorbent body 3 between the liquid-permeable top sheet 2 andliquid-impermeable back sheet 8.

In FIG. 4, the top sheet 2 is formed of a nonwoven fabric, and it has aplurality of projections 21 and a plurality of recesses 22 on the skinside surface 10, with a blood slipping agent 9 coated on the skin sidesurface 10 of the top sheet 2. In FIG. 4, the blood slipping agent 9 isshown as droplets (or particles) on the skin side surface 10 of the topsheet 2 for convenience, but according to the absorbent article of thisdisclosure, the form and distribution of the blood slipping agent is notlimited to that shown in the drawing.

As shown in FIG. 4, menstrual blood 23 that has reached the projections21 of the top sheet 2 contacts with the blood slipping agent 9 that ispresent in the projections 21. A portion of the blood slipping agent 9present in the projections 21 slips down into the recesses 22 togetherwith the menstrual blood 23 (menstrual blood 23′). The menstrual blood23′ then slips down into the recesses 22, reaching the absorbent body 3(menstrual blood 23″). Next, the menstrual blood 23″ is absorbed intothe absorbent body 3.

More specifically, the blood slipping agent 9 having a water holdingpercentage of about 0.01 to about 4.0 mass % has a certain affinity withmenstrual blood 23. For example, the hydrophilic portion of the bloodslipping agent 9 (for example, a hydrophilic group, such as a polargroup, for example, such as carbonyl, oxy, carboxyl, hydroxyl or thelike, or a hydrophilic bond, such as a polar bond, for example, such asa carbonyl bond, ester bond, carbonate bond, ether bond or the like) hashigh affinity with the hydrophilic components (such as blood plasma) inthe menstrual blood 23, and attracts the components with affinity,whereas the hydrophobic portion (for example, the hydrocarbon moiety) ofthe blood slipping agent 9 has low affinity with the hydrophiliccomponents (such as blood plasma) in the menstrual blood 23 and repelsthe hydrophilic components, such that it functions as a “lubricant”,causing the menstrual blood 23 to slip down toward the absorbent body 3.

Also, since the blood slipping agent 9 having a kinematic viscosity ofabout 0.01 to about 80 mm²/s at 40° C. has very low viscosity near thebody temperature of the wearer, a portion thereof slips down from theprojections 21 into the recesses 22 together with the menstrual blood23, subsequently passing through the recesses 22 into the absorbentarticle 1.

Furthermore, since the blood slipping agent 9 has a water holdingpercentage of about 0.01 to about 4.0 mass %, its affinity with thehydrophilic components (such as blood plasma) in menstrual blood 23 isnot excessively high, and this causes less of the menstrual blood 23 toremain on the top sheet 2. This is because the hydrophilic components(such as blood plasma) in the menstrual blood 23 repels the hydrophobicportion of the blood slipping agent 9.

FIG. 4 schematically illustrates migration of menstrual blood into theabsorbent body by the blood slipping agent, for a top sheet 2 formed ofa nonwoven fabric and having a plurality of projections 21 and aplurality of recesses 22 on the skin side surface 10, but menstrualblood also migrates in the same manner in a top sheet withoutirregularities, such as a flat nonwoven fabric or woven fabric, a porousfilm or a flap-like skin side sheet.

This is because in a nonwoven fabric or woven fabric, the blood slippingagent causes the menstrual blood to slip down between the fibers, whilein a porous film, the blood slipping agent causes the menstrual blood toslip down into the pores.

Also, while FIG. 4 schematically illustrates migration of menstrualblood into the absorbent body by the blood slipping agent, a bloodslipping agent-containing composition functions in the same manner.

The blood slipping agent has a weight-average molecular weight of lessthan about 1,000, and preferably a weight-average molecular weight ofless than about 900. This is because, if the weight-average molecularweight is about 1,000 or higher, tack may result in the blood slippingagent itself, tending to create a feeling of unpleasantness for thewearer. If the weight-average molecular weight increases, the viscosityof the blood slipping agent will tend to increase, and it will thereforebe difficult to lower the viscosity of the blood slipping agent byheating to a viscosity suitable for coating, and as a result, the bloodslipping agent may need to be diluted with a solvent.

The blood slipping agent preferably has a weight-average molecularweight of about 100 or greater, and more preferably it has aweight-average molecular weight of about 200 or greater. This is becauseif the weight-average molecular weight is low, the vapor pressure of theblood slipping agent may be increased, gasification may occur duringstorage and the amount may be reduced, often leading to problems, suchas odor during wear.

In addition, as used herein, “weight-average molecular weight” includesthe concept of a polydisperse compound (for example, a compound producedby stepwise polymerization, an ester formed from a plurality of fattyacids and a plurality of aliphatic monohydric alcohols), and a simplecompound (for example, an ester formed from one fatty acid and onealiphatic monohydric alcohol), and in a system comprising N_(i)molecules with molecular weight M_(i) (i=1, or i=1, 2 . . . ), it refersto M_(w) determined by the following formula.M _(w) =ΣN _(i) M _(i) ² /ΣN _(i) M _(i)

As used herein, the weight-average molecular weights are the valuesmeasured by gel permeation chromatography (GPC), based on polystyrene.

The GPC measuring conditions may be the following, for example.

Device: Lachrom Elite high-speed liquid chromatogram by HitachiHigh-Technologies Corp.

Columns: SHODEX KF-801, KF-803 and KF-804, by Showa Denko K.K.

Eluent: THF

Flow rate: 1.0 mL/min

Driving volume: 100μL

Detection: RI (differential refractometer)

The weight-average molecular weights listed in the examples of thepresent specification were measured under the conditions describedbelow.

The blood slipping agent can have an IOB of about 0.00 to about 0.60.

The IOB (Inorganic Organic Balance) is an indicator of thehydrophilic-lipophilic balance, and as used herein, it is the valuecalculated by the following formula by Oda et al.:IOB=inorganic value/organic value.

The inorganic value and the organic value are based on the organicparadigm described in “Organic compound predictions and organicparadigms” by Fujita A., Kagaku no Ryoiki (Journal of JapaneseChemistry), Vol. 11, No. 10 (1957) p. 719-725.

The organic values and inorganic values of major groups, according toFujita, are summarized in Table 1 below.

TABLE 1 Inorganic Organic Group value value —COOH 150 0 —OH 100 0—O—CO—O— 80 0 —CO— 65 0 —COOR 60 0 —O— 20 0 Triple bond 3 0 Double bond2 0 CH₂ 0 20 iso-branch 0 −10 tert-branch 0 −20 Light metal (salt) ≧5000 Heavy metal (salt), ≧400 0 amine, NH₃ salt

For example, in the case of an ester of tetradecanoic acid which has 14carbon atoms and dodecyl alcohol which has 12 carbon atoms, the organicvalue is 520 (CH₂, 20×26) and the inorganic value is 60 (—COOR, 60×1),and therefore IOB=0.12.

The IOB of the blood slipping agent is preferably between about 0.00 and0.60, more preferably between about 0.00 and 0.50, even more preferablybetween about 0.00 and 0.40 and most preferably between about 0.00 and0.30. If the IOB is within this range, it will be easier to meet theaforementioned conditions for the water-holding capacity and kinematicviscosity.

The blood slipping agent preferably has a melting point of no higherthan 45° C., and more preferably it has a melting point of no higherthan 40° C. If the blood slipping agent has a melting point of no higherthan 45° C., the blood slipping agent will more easily exhibit akinematic viscosity in the aforementioned range.

As used herein, the term “melting point” refers to the peak toptemperature for the endothermic peak during conversion from solid toliquid, upon measurement with a differential scanning calorimetryanalyzer at a temperature-elevating rate of 10° C./min. The differentialscanning calorimetry analyzer used may be, for example, a DSC-60-typeDSC measuring apparatus by Shimadzu Corp.

If the blood slipping agent has a melting point of about 45° C. or less,it may be either liquid or solid at room temperature (25° C.), or inother words, the melting point may be either about 25° C. or higher orbelow about 25° C., and for example, it may have a melting point ofabout −5° C. or about −20° C. The reason for a melting point of about45° C. or less for the blood slipping agent will be explained below.

The blood slipping agent does not have a lower limit for the meltingpoint, but the vapor pressure is preferably low. The vapor pressure ofthe blood slipping agent is preferably about 0-200 Pa, more preferablyabout 0-100 Pa, even more preferably about 0-10 Pa, even more preferablyabout 0-1 Pa, and even more preferably about 0.0-0.1 Pa at 25° C. (1atmosphere).

Considering that the absorbent article of this disclosure is to be usedin contact with the human body, the vapor pressure is preferably about0-700 Pa, more preferably about 0-100 Pa, even more preferably about0-10 Pa, even more preferably about 0-1 Pa, and even more preferably0.0-0.1 Pa, at 40° C. (1 atmosphere). If the vapor pressure is high,gasification may occur during storage and the amount of blood slippingagent may be reduced, and as a consequence problems, such as odor duringwear, may be created.

The melting point of the blood slipping agent may be selected dependingon the weather or duration of wear. For example, in regions with a meanatmospheric temperature of about 10° C. or less, using a blood slippingagent with a melting point of about 10° C. or less may help the bloodslipping agent function after excretion of menstrual blood, even if ithas been cooled by the ambient temperature.

Also, when the absorbent article is to be used for a prolonged period oftime, the melting point of the blood slipping agent is preferably at thehigh end of the range of about 45° C. or less. This is so that the bloodslipping agent will not be easily affected by sweat or friction duringwearing, and will not easily become biased even during prolongedwearing.

In the technical field, the skin contact surfaces of top sheets arecoated with surfactants in order to alter the surface tension ofmenstrual blood and promote rapid absorption of menstrual blood.However, the top sheet coated with the surfactant has very high affinityfor the hydrophilic components (blood plasma, etc.) in menstrual blood,and acts to attract them, tending to cause menstrual blood instead toremain on the top sheet. The blood slipping agent, unlike conventionallyknown surfactants, has low affinity with menstrual blood and thereforedoes not cause residue of menstrual blood on the top sheet and allowsrapid migration into the absorbent body.

Preferably, the blood slipping agent is selected from the groupconsisting of following items (i)-(iii), and any combination thereof:

(i) a hydrocarbon;

(ii) a compound having (ii-1) a hydrocarbon moiety, and (ii-2) one ormore, same or different groups selected from the group consisting ofcarbonyl group (—CO—) and oxy group (—O—) inserted between a C—C singlebond of the hydrocarbon moiety; and

(iii) a compound having (iii-1) a hydrocarbon moiety, (iii-2) one ormore, same or different groups selected from the group consisting ofcarbonyl group (—CO—) and oxy group (—O—) inserted between a C—C singlebond of the hydrocarbon moiety, and (iii-3) one or more, same ordifferent groups selected from the group consisting of carboxyl group(—COOH) and hydroxyl group (—OH) substituting for a hydrogen on thehydrocarbon moiety.

As used herein, “hydrocarbon” refers to a compound composed of carbonand hydrogen, and it may be a chain hydrocarbon, such as a paraffinichydrocarbon (containing no double bond or triple bond, also referred toas alkane), an olefin-based hydrocarbon (containing one double bond,also referred to as alkene), an acetylene-based hydrocarbon (containingone triple bond, also referred to as alkyne), or a hydrocarboncomprising two or more bonds selected from the group consisting ofdouble bonds and triple bonds, and cyclic hydrocarbon, such as aromatichydrocarbons and alicyclic hydrocarbons.

Preferred as such hydrocarbons are chain hydrocarbons and alicyclichydrocarbons, with chain hydrocarbons being more preferred, paraffinichydrocarbons, olefin-based hydrocarbons and hydrocarbons with two ormore double bonds (containing no triple bond) being more preferred, andparaffinic hydrocarbons being even more preferred.

Chain hydrocarbons include linear hydrocarbons and branchedhydrocarbons.

When two or more oxy groups (—O—) are inserted in the compounds of (ii)and (iii) above, the oxy groups (—O—) are not adjacent each other. Thus,compounds (ii) and (iii) do not include compounds with continuous oxygroups (i.e., peroxides).

In the compounds of (iii), compounds in which at least one hydrogen onthe hydrocarbon moiety is substituted with a hydroxyl group (—OH) arepreferred over compounds in which at least one hydrogen on thehydrocarbon moiety is substituted with a carboxyl group (—COOH). This isbecause the carboxyl groups bond with metals and the like in menstrualblood, increasing the water holding percentage of the blood slippingagent, which may sometimes exceed the prescribed range. The same is truefrom the viewpoint of the IOB as well. As shown in Table 1, the carboxylgroups bond with metals and the like in menstrual blood, drasticallyincreasing the inorganic value from 150 to 400 or greater, and thereforea blood slipping agent with carboxyl groups can increase the IOB valueto more than about 0.60 during use.

More preferably, the blood slipping agent is selected from the groupconsisting of following items (i′)-(iii′), and any combination thereof:

(i′) a hydrocarbon;

(ii′) a compound having (ii′-1) a hydrocarbon moiety, and (ii′-2) one ormore, same or different bonds selected from the group consisting ofcarbonyl bond (—CO—), ester bond (—COO—), carbonate bond (—OCOO—), andether bond (—O—) inserted between a C—C single bond of the hydrocarbonmoiety; and

(iii′) a compound having (iii′-1) a hydrocarbon moiety, (iii′-2) one ormore, same or different bonds selected from the group consisting ofcarbonyl bond (—CO—), ester bond (—COO—), carbonate bond (—OCOO—), andether bond (—O—) inserted between a C—C single bond of the hydrocarbonmoiety, and (iii′-3) one or more, same or different groups selected fromthe group consisting of carboxyl group (—COOH) and hydroxyl group (—OH)substituting for a hydrogen on the hydrocarbon moiety.

When 2 or more same or different bonds are inserted in the compound of(ii′) or (iii′), i.e., when 2 or more same or different bonds selectedfrom the group consisting carbonyl bonds (—CO—), ester bonds (—COO—),carbonate bonds (—OCOO—) and ether bonds (—O—) are inserted, the bondsare not adjacent to each other, and at least one carbon atom liesbetween each of the bonds.

The blood slipping agent has more preferably about 1.8 or less carbonylbonds (—CO—), about 2 or less ester bonds (—COO—), about 1.5 or lesscarbonate bonds (—OCOO—), about 6 or less ether bonds (—O—), about 0.8or less carboxyl groups (—COOH) and/or about 1.2 or less hydroxyl groups(—OH), per 10 carbon atoms in the hydrocarbon moiety.

Even more preferably, the blood slipping agent is selected from thegroup consisting of following items (A)-(F), and any combinationthereof:

(A) an ester of (A1) a compound having a chain hydrocarbon moiety and2-4 hydroxyl groups substituting for hydrogens on the chain hydrocarbonmoiety, and (A2) a compound having a chain hydrocarbon moiety and 1carboxyl group substituting for a hydrogen on the chain hydrocarbonmoiety;

(B) an ether of (B1) a compound having a chain hydrocarbon moiety and2-4 hydroxyl groups substituting for hydrogens on the chain hydrocarbonmoiety, and (B2) a compound having a chain hydrocarbon moiety and 1hydroxyl group substituting for a hydrogen on the chain hydrocarbonmoiety;

(C) an ester of (C1) a carboxylic acid, hydroxy acid, alkoxy acid oroxoacid comprising a chain hydrocarbon moiety and 2-4 carboxyl groupssubstituting for hydrogens on the chain hydrocarbon moiety, and (C2) acompound having a chain hydrocarbon moiety and 1 hydroxyl groupsubstituting for a hydrogen on the chain hydrocarbon moiety;

(D) a compound having a chain hydrocarbon moiety and one bond selectedfrom the group consisting of ether bonds (—O—), carbonyl bonds (—CO—),ester bonds (—COO—) and carbonate bonds (—OCOO—) inserted between a C—Csingle bond of the chain hydrocarbon moiety;

(E) a polyoxy C₃-C₆ alkylene glycol, or ester or ether thereof; and

(F) a chain hydrocarbon.

The blood slipping agent in accordance with (A) to (F) will now bedescribed in detail.

[(A) Ester of (A1) a Compound having a Chain Hydrocarbon Moiety and 2-4Hydroxyl Groups Substituting for Hydrogens on the Chain HydrocarbonMoiety, and (A2) a Compound having a Chain Hydrocarbon Moiety and 1Carboxyl Group Substituting for a Hydrogen on the Chain HydrocarbonMoiety]

In the (A) ester of (A1) a compound having a chain hydrocarbon moietyand 2-4 hydroxyl groups substituting for hydrogens on the chainhydrocarbon moiety, and (A2) a compound having a chain hydrocarbonmoiety and 1 carboxyl group substituting for a hydrogen on the chainhydrocarbon moiety (hereunder also referred to as “compound (A)”), it isnot necessary for all of the hydroxyl groups to be esterified so long asthe kinematic viscosity, water holding percentage and weight-averagemolecular weight are within the aforementioned ranges.

Examples of (A1) a compound having a chain hydrocarbon moiety and 2-4hydroxyl groups substituting for hydrogens on the chain hydrocarbonmoiety (hereunder also referred to as “compound (A1)”) include chainhydrocarbon tetraols, such as alkanetetraols, including pentaerythritol,chain hydrocarbon triols, such as alkanetriols, including glycerins, andchain hydrocarbon diols, such as alkanediols, including glycols.

Examples of (A2) a compound having a chain hydrocarbon moiety and 1carboxyl group substituting for a hydrogen on the chain hydrocarbonmoiety include compounds in which one hydrogen on the hydrocarbon issubstituted with one carboxyl group (—COOH), such as fatty acids.

Examples for compound (A) include (a₁) an ester of a chain hydrocarbontetraol and at least one fatty acid, (a₂) an ester of a chainhydrocarbon triol and at least one fatty acid, and (a₃) an ester of achain hydrocarbon diol and at least one fatty acids.

[(a₁) Esters of a Chain Hydrocarbon Tetraol and at Least One Fatty Acid]

Examples of an ester of a chain hydrocarbon tetraol and at least onefatty acid include tetraesters of pentaerythritol and fatty acids,represented by the following formula (1):

triesters of pentaerythritol and fatty acids, represented by thefollowing formula (2):

diesters of pentaerythritol and fatty acids, represented by thefollowing formula (3):

and monoesters of pentaerythritol and fatty acids, represented by thefollowing formula (4).

In the formulas, R¹-R⁴ each represent a chain hydrocarbon.

The fatty acids consisting of the esters of pentaerythritol and fattyacids (R¹COOH, R²COOH, R³COOH, and R⁴COOH) are not particularlyrestricted so long as the pentaerythritol and fatty acid esters satisfythe conditions for the kinematic viscosity, water holding percentage andweight-average molecular weight, and for example, there may be mentionedsaturated fatty acids, such as a C₂-C₃₀ saturated fatty acids, includingacetic acid (C₂) (C₂ representing the number of carbons, correspondingto the number of carbons of each of R¹C, R²C, R³C or R⁴C, samehereunder), propanoic acid (C₃), butanoic acid (C₄) and isomers thereof,such as 2-methylpropanoic acid (C₄), pentanoic acid (C₅) and isomersthereof, such as 2-methylbutanoic acid (C₅) and 2,2-dimethylpropanoicacid (C₅), hexanoic acid (C₆), heptanoic acid (C₇), octanoic acid (C₈)and isomers thereof, such as 2-ethylhexanoic acid (C₈), nonanoic acid(C₉), decanoic acid (C₁₀), dodecanoic acid (C₁₂), tetradecanoic acid(C₁₄), hexadecanoic acid (C₁₆), heptadecanoic acid (C₁₇), octadecanoicacid (C₁₈), eicosanoic acid (C₂₀), docosanoic acid (C₂₂), tetracosanoicacid (C₂₄), hexacosanoic acid (C₂₆), octacosanoic acid (C₂₈),triacontanoic acid (C₃₀), as well as isomers thereof which are notdescribed above.

The fatty acid may also be an unsaturated fatty acid. Examples ofunsaturated fatty acids include C₃-C₂₀ unsaturated fatty acids, such asmonounsaturated fatty acids including crotonic acid (C₄), myristoleicacid (C₁₄), palmitoleic acid (C₁₆), oleic acid (C₁₈), elaidic acid(C₁₈), vaccenic acid (C₁₈), gadoleic acid (C₂₀) and eicosenoic acid(C₂₀), di-unsaturated fatty acids including linolic acid (C₁₈) andeicosadienoic acid (C₂₀), tri-unsaturated fatty acids includinglinolenic acids, such as α-linolenic acid (C₁₈) and γ-linolenic acid(C₁₈), pinolenic acid (C₁₈), eleostearic acids, such as α-eleostearicacid (C₁₈) and β-eleostearic acid (C₁₈), Mead acid (C₂₀),dihomo-γ-linolenic acid (C₂₀) and eicosatrienoic acid (C₂₀),tetra-unsaturated fatty acids including stearidonic acid (C₂₀),arachidonic acid (C₂₀) and eicosatetraenoic acid (C₂₀),penta-unsaturated fatty acids including bosseopentaenoic acid (C₁₈) andeicosapentaenoic acid (C₂₀), and partial hydrogen adducts thereof.

Considering the potential for degradation by oxidation and the like, theester of pentaerythritol and a fatty acid is preferably an ester ofpentaerythritol and a fatty acid, which is derived from a saturatedfatty acid, i.e., an ester of pentaerythritol and a saturated fattyacid.

Also, from the viewpoint of lowering the water holding percentage, theester of pentaerythritol and a fatty acid is preferably a diester,triester or tetraester, more preferably a triester or tetraester, andeven more preferably a tetraester.

From the viewpoint of the IOB being from about 0.00 to about 0.60, in atetraester of pentaerythritol and a fatty acid, the total number ofcarbons of the fatty acid composing the tetraester of thepentaerythritol and fatty acid, i.e. the total number of carbons of theR¹C, R²C, R³C and R⁴C portions in formula (1), is preferably about 15(the IOB is 0.60 when the total number of carbon atoms is 15).

Examples of tetraesters of pentaerythritol and fatty acids includetetraesters of pentaerythritol with hexanoic acid (C₆), heptanoic acid(C₇), octanoic acid (C₈), such as 2-ethylhexanoic acid (C₈), nonanoicacid (C₉), decanoic acid (C₁₀) and/or dodecanoic acid (C₁₂).

From the viewpoint of the IOB being from about 0.00 to about 0.60, in atriester of pentaerythritol and a fatty acid, the total number ofcarbons of the fatty acid composing the triester of the pentaerythritoland fatty acid, i.e. the total number of carbons of the R¹C, R²C and R³Cportions in formula (2), is preferably about 19 or greater (the IOB is0.58 when the number of carbon atoms is 19).

From the viewpoint of the IOB being from about 0.00 to about 0.60, in adiester of pentaerythritol and a fatty acid, the total number of carbonsof the fatty acid composing the diester of the pentaerythritol and fattyacid, i.e. the total number of carbons of the R¹C and R²C portion informula (3), is preferably about 22 or greater (the IOB is 0.59 when thenumber of carbon atoms is 22).

From the viewpoint of the IOB being from about 0.00 to about 0.60, in amonoester of pentaerythritol and a fatty acid, the total number ofcarbons of the fatty acid composing the monoester of the pentaerythritoland fatty acid, i.e. the number of carbons of the R¹C portion in formula(4), is preferably about 25 or greater (the IOB is 0.60 when the numberof carbon atoms is 25).

The effects of double bonds, triple bonds, iso-branches andtert-branches are not considered in this calculation of the IOB (samehereunder).

Commercial products which are esters of pentaerythritol and fatty acidsinclude UNISTAR H-408BRS and H-2408BRS-22 (mixed product) (both productsof NOF Corp.).

[(a₂) Ester of a Chain Hydrocarbon Triol and at Least One Fatty Acid]

Examples of esters of a chain hydrocarbon triol and at least one fattyacid include triesters of glycerin and fatty acids, represented byformula (5):

diesters of glycerin and fatty acids, represented by the followingformula (6):

and monoesters of glycerin and fatty acids, represented by the followingformula (7):

wherein R⁵-R⁷ each represent a chain hydrocarbon.

The fatty acid consisting of the ester of glycerin and a fatty acid(R⁵COOH, R⁶COOH and R⁷COOH) is not particularly restricted so long asthe ester of glycerin and a fatty acid satisfies the conditions for thekinematic viscosity, water holding percentage and weight-averagemolecular weight, and for example, there may be mentioned the fattyacids mentioned for the “(a₁) Ester of a chain hydrocarbon tetraol andat least one fatty acid”, namely saturated fatty acids and unsaturatedfatty acids, and in consideration of the potential for degradation byoxidation and the like, the ester is preferably a glycerin and fattyacid ester, which is derived from a saturated fatty acid, i.e., an esterof glycerin and a saturated fatty acid.

Also, from the viewpoint of lowering the water holding percentage andresult in greater hydrophobicity, the ester of glycerin and a fatty acidis preferably a diester or triester, and more preferably a triester.

A triester of glycerin and a fatty acid is also known as a triglyceride,and examples include triesters of glycerin and octanoic acid (C₈),triesters of glycerin and decanoic acid (C₁₀), triesters of glycerin anddodecanoic acid (C₁₂), triesters of glycerin and 2 or 3 different fattyacids, and mixtures thereof.

Examples of triesters of glycerin and 2 or more fatty acids includetriesters of glycerin with octanoic acid (C₈) and decanoic acid (C₁₀),triesters of glycerin with octanoic acid (C₈), decanoic acid (C₁₀) anddodecanoic acid (C₁₂), and triesters of glycerin with octanoic acid(C₈), decanoic acid (C₁₀), dodecanoic acid (C₁₂), tetradecanoic acid(C₁₄), hexadecanoic acid (C₁₆) and octadecanoic acid (C₁₈).

In order to obtain a melting point of about 45° C. or less, preferredtriesters of glycerin and fatty acids are those with about 40 or less asthe total number of carbons of the fatty acid consisting of the triesterof glycerin and the fatty acid, i.e., the total number of carbons of theR⁵C, R⁶C and R⁷C sections in formula (5).

From the viewpoint of the IOB being from about 0.00 to about 0.60, in atriester of glycerin and a fatty acid, the total number of carbons ofthe fatty acid composing the triester of the glycerin and fatty acid,i.e. the total number of carbons of the R⁵C, R⁶C and R⁷C portions informula (5), is preferably about 12 or greater (the IOB is 0.60 when thetotal number of carbon atoms is 12).

Triesters of glycerin and fatty acids, being aliphatic and thereforepotential constituent components of the human body, are preferred fromthe viewpoint of safety.

Commercial products of triesters of glycerin and fatty acids includetri-coconut fatty acid glycerides, NA36, PANACET 800, PANACET 800B andPANACET 810S, and tri-C2L oil fatty acid glycerides and tri-CL oil fattyacid glycerides (all products of NOF Corp.).

A diester of glycerin and a fatty acid is also known as a diglyceride,and examples include diesters of glycerin and decanoic acid (C₁₀),diesters of glycerin and dodecanoic acid (C₁₂), diesters of glycerin andhexadecanoic acid (C₁₆), diesters of glycerin and 2 or more differentfatty acids, and mixtures thereof.

From the viewpoint of the IOB being from about 0.00 to about 0.60, in adiester of glycerin and a fatty acid, the total number of carbons of thefatty acid composing the diester of the glycerin and fatty acid, i.e.the total number of carbons of the R⁵C and R⁶C portions in formula (6),is preferably about 16 or greater (the IOB is 0.58 when the total numberof carbon atoms is 16).

Monoesters of glycerin and fatty acids are also known as monoglycerides,and examples include glycerin and octadecanoic acid (C₁₈) monoester, andglycerin and docosanoic acid (C₂₂) monoester.

From the viewpoint of the IOB being from about 0.00 to about 0.60, in amonoester of glycerin and a fatty acid, the total number of carbons ofthe fatty acid composing the monoester of the glycerin and fatty acid,i.e. the number of carbons of the R⁵C portion in formula (7), ispreferably about 19 or greater (the IOB is 0.59 when the number ofcarbon atoms is 19).

[(a₃) Ester of a Chain Hydrocarbon Diol and at Least One Fatty Acid]

Examples of an ester of a chain hydrocarbon diol and at least one fattyacid include monoesters and diesters of fatty acids with C₂-C₆ chainhydrocarbon diols, such as C₂-C₆ glycols, including ethylene glycol,propylene glycol, butylene glycol, pentylene glycol and hexylene glycol.

Specifically, examples of an ester of a chain hydrocarbon diol and atleast one fatty acid include diesters of C₂-C₆ glycols and fatty acids,represented by the following formula (8):R⁸COOC_(k)H_(2k)OCOR⁹  (8)

wherein k represents an integer of 2-6, and R⁸ and R⁹ each represent achain hydrocarbon, and monoesters of C₂-C₆ glycols and fatty acids,represented by the following formula (9):R⁸COOC_(k)H_(2k)OH  (9)

wherein k represents an integer of 2-6, and R⁸ is a chain hydrocarbon.

The fatty acid to be esterified in an ester of a C₂-C₆ glycol and afatty acid (corresponding to R⁸COOH and R⁹COOH in formula (8) andformula (9)) is not particularly restricted so long as the ester of theC₂-C₆ glycol and fatty acid satisfies the conditions for the kinematicviscosity, water holding percentage and weight-average molecular weight,and for example, there may be mentioned the fatty acids mentioned abovefor the “(a₁) Ester of a chain hydrocarbon tetraol and at least onefatty acid”, namely saturated fatty acids and unsaturated fatty acids,and in consideration of the potential for degradation by oxidation andthe like, it is preferably a saturated fatty acid.

From the viewpoint of the IOB being from about 0.00 to about 0.60, in adiester of butylene glycol represented by formula (8) (k=4) and a fattyacid, the total number of carbons of the R⁸C and R⁹C portions ispreferably about 6 or greater (the IOB is 0.60 when the total number ofcarbon atoms is 6).

From the viewpoint of the IOB being from about 0.00 to about 0.60, in amonoester of ethylene glycol represented by formula (9) (k=2) and afatty acid, the number of carbons of the R⁸C portion is preferably about12 or greater (the IOB is 0.57 when the number of carbon atoms is 12).

Considering the potential for degradation by oxidation and the like, theester of the C₂-C₆ glycol and fatty acid is preferably a C₂-C₆ glycoland fatty acid ester derived from a saturated fatty acid, or in otherwords, an ester of a C₂-C₆ glycol and a saturated fatty acid.

Also, from the viewpoint of lowering the water holding percentage, theester of the C₂-C₆ glycol and fatty acid is preferably a glycol andfatty acid ester derived from a glycol with a greater number of carbons,such as an ester of a glycol and a fatty acid derived from butyleneglycol, pentylene glycol or hexylene glycol.

Also, from the viewpoint of lowering the water holding percentage, theester of a C₂-C₆ glycol and fatty acid is preferably a diester.

Examples of commercial products of esters of C₂-C₆ glycols and fattyacids include COMPOL BL and COMPOL BS (both products of NOF Corp.).

[(B) Ether of (B1) a Compound having a Chain Hydrocarbon Moiety and 2-4Hydroxyl Groups Substituting for Hydrogens on the Chain HydrocarbonMoiety and (B2) a Compound having a Chain Hydrocarbon Moiety and 1Hydroxyl Group Substituting for a Hydrogen on the Chain HydrocarbonMoiety]

In the (B) ether of (B1) a compound having a chain hydrocarbon moietyand 2-4 hydroxyl groups substituting for hydrogens on the chainhydrocarbon moiety and (B2) a compound having a chain hydrocarbon moietyand 1 hydroxyl group substituting for a hydrogen on the chainhydrocarbon moiety (hereunder also referred to as “compound (B)”), it isnot necessary for all of the hydroxyl groups to be etherified so long asthe kinematic viscosity, water holding percentage and weight-averagemolecular weight are within the aforementioned ranges.

Examples of (B1) a compound having a chain hydrocarbon moiety and 2-4hydroxyl groups substituting for hydrogens on the chain hydrocarbonmoiety (hereunder also referred to as “compound (B1)”) include thosementioned for “compound (A)” as compound (A1), such as pentaerythritol,glycerin and glycol.

Examples of (B2) a compound having a chain hydrocarbon moiety and 1hydroxyl group substituting for a hydrogen on the chain hydrocarbonmoiety (hereunder also referred to as “compound (B2)”) include compoundswherein 1 hydrogen on the hydrocarbon is substituted with 1 hydroxylgroup (—OH), such as aliphatic monohydric alcohols, including saturatedaliphatic monohydric alcohols and unsaturated aliphatic monohydricalcohols.

Examples of saturated aliphatic monohydric alcohols include C₁-C₂₀saturated aliphatic monohydric alcohols, such as methyl alcohol (C₁) (C₁representing the number of carbon atoms, same hereunder), ethyl alcohol(C₂), propyl alcohol (C₃) and isomers thereof, including isopropylalcohol (C₃), butyl alcohol (C₄) and isomers thereof, includingsec-butyl alcohol (C₄) and tert-butyl alcohol (C₄), pentyl alcohol (C₅),hexyl alcohol (C₆), heptyl alcohol (C₇), octyl alcohol (C₈) and isomersthereof, including 2-ethylhexyl alcohol (C₈), nonyl alcohol (C₉), decylalcohol (C₁₀), dodecyl alcohol (C₁₂), tetradecyl alcohol (C₁₄),hexadecyl alcohol (C₁₆), heptadecyl alcohol (C₁₇), octadecyl alcohol(C₁₈) and eicosyl alcohol (C₂₀), as well as their isomers other thanthose mentioned.

Unsaturated aliphatic monohydric alcohols include those wherein 1 C—Csingle bond of a saturated aliphatic monohydric alcohol mentioned aboveis replaced with a C═C double bond, such as oleyl alcohol, and forexample, such alcohols are commercially available by New Japan ChemicalCo., Ltd. as the RIKACOL Series and UNJECOL Series.

Examples for compound (B) include (b₁) an ether of a chain hydrocarbontetraol and at least one aliphatic monohydric alcohol, such asmonoethers, diethers, triethers and tetraethers, preferably diethers,triethers and tetraethers, more preferably triethers and tetraethers andeven more preferably tetraethers, (b₂) an ether of a chain hydrocarbontriol and at least one aliphatic monohydric alcohol, such as monoethers,diethers and triethers, preferably diethers and triethers and morepreferably triethers, and (b₃) an ether of a chain hydrocarbon diol andat least one aliphatic monohydric alcohol, such as monoethers anddiethers, and preferably diethers.

Examples of an ether of a chain hydrocarbon tetraol and at least onealiphatic monohydric alcohol include tetraethers, triethers, diethersand monoethers of pentaerythritol and aliphatic monohydric alcohols,represented by the following formulas (10)-(13):

wherein R¹⁰-R¹³ each represent a chain hydrocarbon.

Examples of an ether of a chain hydrocarbon triol and at least onealiphatic monohydric alcohol include triethers, diethers and monoethersof glycerin and aliphatic monohydric alcohols, represented by thefollowing formulas (14)-(16):

wherein R¹⁴-R¹⁶ each represent a chain hydrocarbon.

Examples of an ether of a chain hydrocarbon diol and at least onealiphatic monohydric alcohol include diethers of C₂-C₆ glycols andaliphatic monohydric alcohols, represented by the following formula(17):R¹⁷OC_(n)H_(2n)OR¹⁸  (17)

wherein n is an integer of 2-6, and R¹⁷ and R¹⁸ are each a chainhydrocarbon,

and monoethers of C₂-C₆ glycols and aliphatic monohydric alcohols,represented by the following formula (18):R¹⁷OC_(n)H_(2n)OH  (18)

wherein n is an integer of 2-6, and R¹⁷ is a chain hydrocarbon.

From the viewpoint of the IOB being between about 0.00 and about 0.60,in a tetraether of pentaerythritol and an aliphatic monohydric alcohol,the total number of carbon atoms of the aliphatic monohydric alcoholcomposing the tetraether of pentaerythritol and the aliphatic monohydricalcohol, i.e. the total number of carbon atoms of the R¹⁰, R¹¹, R¹² andR¹³ portions in formula (10), is preferably about 4 or greater (the IOBis 0.44 when the total number of carbon atoms is 4).

From the viewpoint of the IOB being between about 0.00 and about 0.60,in a triether of pentaerythritol and an aliphatic monohydric alcohol,the total number of carbon atoms of the aliphatic monohydric alcoholcomposing the triether of pentaerythritol and the aliphatic monohydricalcohol, i.e. the total number of carbon atoms of the R¹⁰, R¹¹ and R¹²portions in formula (11), is preferably about 9 or greater (the IOB is0.57 when the total number of carbon atoms is 9).

From the viewpoint of the IOB being between about 0.00 and about 0.60,in a diether of pentaerythritol and an aliphatic monohydric alcohol, thetotal number of carbon atoms of the aliphatic monohydric alcoholcomposing the diether of pentaerythritol and the aliphatic monohydricalcohol, i.e. the total number of carbon atoms of the R¹⁰ and R¹¹portions in formula (12), is preferably about 15 or greater (the IOB is0.60 when the total number of carbon atoms is 15).

From the viewpoint of the IOB being between about 0.00 and about 0.60,in a monoether of pentaerythritol and an aliphatic monohydric alcohol,the number of carbon atoms of the aliphatic monohydric alcohol composingthe monoether of pentaerythritol and the aliphatic monohydric alcohol,i.e. the number of carbon atoms of the R¹⁰ portion in formula (13), ispreferably about 22 or greater (the IOB is 0.59 when the number ofcarbon atoms is 22).

From the viewpoint of the IOB being between about 0.00 and about 0.60,in a triether of glycerin and an aliphatic monohydric alcohol, the totalnumber of carbon atoms of the aliphatic monohydric alcohol composing thetriether of glycerin and the aliphatic monohydric alcohol, i.e. thetotal number of carbon atoms of the R¹⁴, R¹⁵ and R¹⁶ portions in formula(14), is preferably about 3 or greater (the IOB is 0.50 when the totalnumber of carbon atoms is 3).

From the viewpoint of the IOB being between about 0.00 and about 0.60,in a diether of glycerin and an aliphatic monohydric alcohol, the totalnumber of carbon atoms of the aliphatic monohydric alcohol composing thediether of glycerin and the aliphatic monohydric alcohol, i.e. the totalnumber of carbon atoms of the R¹⁴ and R¹⁵ portions in formula (15), ispreferably about 9 or greater (the IOB is 0.58 when the total number ofcarbon atoms is 9).

From the viewpoint of the IOB being between about 0.00 and about 0.60,in a monoether of glycerin and an aliphatic monohydric alcohol, thenumber of carbon atoms of the aliphatic monohydric alcohol composing themonoether of glycerin and the aliphatic monohydric alcohol, i.e. thenumber of carbon atoms of the R¹⁴ portion in formula (16), is preferably16 or greater (the IOB is 0.58 when the number of carbon atoms is 16).

From the viewpoint of the IOB being from about 0.00 to about 0.60, in adiether of butylene glycol represented by formula (17) (n=4) and analiphatic monohydric alcohol, the total number of carbon atoms of theR¹⁷ and R¹⁸ portions is preferably about 2 or greater (the IOB is 0.33when the total number of carbon atoms is 2).

From the viewpoint of the IOB being from about 0.00 to about 0.60, in amonoether of ethylene glycol represented by formula (18) (n=2) and analiphatic monohydric alcohol, the number of carbon atoms of the R¹⁷portion is preferably about 8 or greater (the IOB is 0.60 when thenumber of carbon atoms is 8).

Compound (B) may be produced by dehydrating condensation of compound(B1) and compound (B2) in the presence of an acid catalyst.

[(C) Ester of (C1) a Carboxylic Acid, Hydroxy Acid, Alkoxy Acid orOxoacid Comprising a Chain Hydrocarbon Moiety and 2-4 Carboxyl GroupsSubstituting for Hydrogens on the Chain Hydrocarbon Moiety and (C2) aCompound having a Chain Hydrocarbon Moiety and 1 Hydroxyl GroupSubstituting for a Hydrogen on the Chain Hydrocarbon Moiety]

In the (C) ester of (C1) a carboxylic acid, hydroxy acid, alkoxy acid oroxoacid comprising a chain hydrocarbon moiety and 2-4 carboxyl groupssubstituting for hydrogens on the chain hydrocarbon moiety and (C2) acompound having a chain hydrocarbon moiety and 1 hydroxyl groupsubstituting for a hydrogen on the chain hydrocarbon moiety (hereunderalso referred to as “compound (C)”), it is not necessary for all of thecarboxyl groups to be esterified so long as the kinematic viscosity,water holding percentage and weight-average molecular weight are withinthe aforementioned ranges.

Examples of (C1) a carboxylic acid, hydroxy acid, alkoxy acid or oxoacidcomprising a chain hydrocarbon moiety and 2-4 carboxyl groupssubstituting for hydrogens on the chain hydrocarbon moiety (hereunderalso referred to as “compound (C1)”) include chain hydrocarboncarboxylic acids with 2-4 carboxyl groups, such as chain hydrocarbondicarboxylic acids including alkanedicarboxylic acids, such asethanedioic acid, propanedioic acid, butanedioic acid, pentanedioicacid, hexanedioic acid, heptanedioic acid, octanedioic acid, nonanedioicacid and decanedioic acid, chain hydrocarbon tricarboxylic acids,including alkanetricarboxylic acids, such as propanetrioic acid,butanetrioic acid, pentanetrioic acid, hexanetrioic acid, heptanetrioicacid, octanetrioic acid, nonanetrioic acid and decanetrioic acid, andchain hydrocarbon tetracarboxylic acids, including alkanetetracarboxylicacids, such as butanetetraoic acid, pentanetetraoic acid, hexanetetraoicacid, heptanetetraoic acid, octanetetraoic acid, nonanetetraoic acid anddecanetetraoic acid.

Compound (C1) includes chain hydrocarbon hydroxy acids with 2-4 carboxylgroups, such as malic acid, tartaric acid, citric acid and isocitricacid, chain hydrocarbon alkoxy acids with 2-4 carboxyl groups, such asO-acetylcitric acid, and chain hydrocarbon oxoacids with 2-4 carboxylgroups.

(C2) Compound having a chain hydrocarbon moiety and 1 hydroxyl groupsubstituting for a hydrogen on the chain hydrocarbon moiety includesthose mentioned for “compound (B)”, such as aliphatic monohydricalcohols.

Compound (C) may be (c₁) an ester, for example a monoester, diester,triester or tetraester, preferably a diester, triester or tetraester,more preferably a triester or tetraester and even more preferably atetraester, of a chain hydrocarbon tetracarboxylic acid, hydroxy acid,alkoxy acid or oxoacid with 4 carboxyl groups, and at least onealiphatic monohydric alcohol, (c₂) an ester, for example, a monoester,diester or triester, preferably a diester or triester and morepreferably a triester, of a chain hydrocarbon tricarboxylic acid,hydroxy acid, alkoxy acid or oxoacid with 3 carboxyl groups, and atleast one aliphatic monohydric alcohol, or (c₃) an ester, for example, amonoester or diester, and preferably a diester, of a chain hydrocarbondicarboxylic acid, hydroxy acid, alkoxy acid or oxoacid with 2 carboxylgroups, and at least one aliphatic monohydric alcohol.

Examples for compound (C) include dioctyl adipate, and tributylO-acetylcitrate, of which commercially available products exist.

[(D) Compound having a Chain Hydrocarbon Moiety and One Bond Selectedfrom the Group Consisting of an Ether Bond (—O—), Carbonyl Bond (—CO—),Ester Bond (—COO—) and Carbonate Bond (—OCOO—) Inserted between a C—CSingle Bond of the Chain Hydrocarbon Moiety]

The (D) compound having a chain hydrocarbon moiety and one bond selectedfrom the group consisting of an ether bond (—O—), carbonyl bond (—CO—),ester bond (—COO—) and carbonate bond (—OCOO—) inserted between a C—Csingle bond of the chain hydrocarbon moiety (hereunder also referred toas “compound (D)”) may be (d₁) an ether of an aliphatic monohydricalcohol and an aliphatic monohydric alcohol, (d₂) a dialkyl ketone, (d₃)an ester of a fatty acid and an aliphatic monohydric alcohol, or (d₄) adialkyl carbonate.

[(d₁) Ether of an Aliphatic Monohydric Alcohol and an AliphaticMonohydric Alcohol]

Ethers of an aliphatic monohydric alcohol and an aliphatic monohydricalcohol include compounds having the following formula (19):R¹⁹OR²⁰  (19)

wherein R¹⁹ and R²⁰ each represent a chain hydrocarbon.

The aliphatic monohydric alcohol consisting of the ether (correspondingto R¹⁹OH and R²⁰OH in formula (19)) is not particularly restricted solong as the ether satisfies the conditions for the kinematic viscosity,water holding percentage and weight-average molecular weight, and forexample, it may be one of the aliphatic monohydric alcohols mentionedfor “compound (B)”.

[(d₂) Dialkyl Ketone]

The dialkyl ketone may be a compound of the following formula (20):R²¹COR²²  (20)

wherein R²¹ and R²² are each an alkyl group.

The dialkyl ketone may be a commercially available product, or it may beobtained by a known method, such as by oxidation of a secondary alcoholwith chromic acid or the like.

[(d₃) Ester of a Fatty Acid and an Aliphatic Monohydric Alcohol]

Examples of esters of a fatty acid and an aliphatic monohydric alcoholinclude compounds having the following formula (21):R²³COOR²⁴  (21)

wherein R²³ and R²⁴ each represent a chain hydrocarbon.

Examples of fatty acids consisting of these esters (corresponding toR²³COOH in formula (21)) include the fatty acids mentioned for the “(a₁)an ester of a chain hydrocarbon tetraol and at least one fatty acids”,and specifically these include saturated fatty acids and unsaturatedfatty acids, with saturated fatty acids being preferred in considerationof the potential for degradation by oxidation and the like. Thealiphatic monohydric alcohol consisting of the ester (corresponding toR²⁴OH in formula (21)) may be one of the aliphatic monohydric alcoholsmentioned for “compound (B)”.

Examples of esters of such fatty acids and aliphatic monohydric alcoholsinclude esters of dodecanoic acid (C₁₂) and dodecyl alcohol (C₁₂) andesters of tetradecanoic acid (C₁₄) and dodecyl alcohol (C₁₂), andexamples of commercial products of esters of such fatty acids andaliphatic monohydric alcohols include ELECTOL WE20 and ELECTOL WE40(both products of NOF Corp.).

[(d₄) Dialkyl Carbonate]

The dialkyl carbonate may be a compound of the following formula (22):R²⁵OC(═O)OR²⁶  (22)

wherein R²⁵ and R²⁶ are each an alkyl group.

The dialkyl carbonate may be a commercially available product, or it maybe synthesized by reaction between phosgene and an alcohol, reactionbetween formic chloride and an alcohol or alcoholate, or reactionbetween silver carbonate and an alkyl iodide.

From the viewpoint of the water holding percentage and vapor pressure,the weight-average molecular weight is preferably about 100 or greaterand more preferably about 200 or greater, for (d₁) an ether of analiphatic monohydric alcohol and an aliphatic monohydric alcohol, (d₂) adialkyl ketone, (d₃) an ester of a fatty acid and an aliphaticmonohydric alcohol, and (d₄) a dialkyl carbonate.

If the total number of carbon atoms is about 8 in a (d₂) dialkyl ketone,the melting point will be approximately −50° C. and the vapor pressurewill be about 230 Pa at 20° C., in the case of 5-nonanone, for example.

[(E) Polyoxy C₃-C₆ Alkylene Glycol, or Alkyl Ester or Alkyl EtherThereof]

The (E) polyoxy C₃-C₆ alkylene glycol, or alkyl ester or alkyl etherthereof (hereunder also referred to as “compound (E)”) may be (e₁) apolyoxy C₃-C₆ alkylene glycol, (e₂) an ester of a polyoxy C₃-C₆ alkyleneglycol and at least one fatty acid, or (e₃) an ether of a polyoxy C₃-C₆alkylene glycol and at least one aliphatic monohydric alcohol. Thesewill now be explained.

[(e₁) Polyoxy C₃-C₆ Alkylene Glycol]

Polyoxy C₃-C₆ alkylene glycols refer to i) homopolymers having one unitselected from the group consisting of oxy C₃-C₆ alkylene units, such asoxypropylene unit, oxybutylene unit, oxypentylene unit and oxyhexyleneunit and having hydroxyl groups at both ends, ii) block copolymershaving 2 or more units selected from oxy C₃-C₆ alkylene units describedabove and oxyhexylene unit and having hydroxyl groups at both ends, oriii) random copolymers having 2 or more units selected from oxy C₃-C₆alkylene units described above and having hydroxyl groups at both ends.

The polyoxy C₃-C₆ alkylene glycol can be represented by the followingformula (23):HO—(C_(m)H_(2m)O)_(n)—H  (23)

wherein m represents an integer of 3-6.

The present inventors have found that with polypropylene glycol(corresponding to a homopolymer of formula (23) where m=3), thecondition for the water holding percentage is not satisfied when theweight-average molecular weight is less than about 1,000. Therefore,polypropylene glycol homopolymer is not included in the scope of theblood slipping agent described above, and propylene glycol should beincluded in the (e₁) polyoxy C₃-C₆ alkylene glycol only as a copolymeror random polymer with another glycol.

Incidentally, investigation by the present inventors suggests that withpolyethylene glycol (corresponding to a homopolymer of formula (23)where m=2), the condition for the kinematic viscosity and water holdingpercentage cannot be satisfied when the weight-average molecular weightis less than about 1,000.

From the viewpoint of the IOB being about 0.00 to about 0.60, whenformula (23) is polybutylene glycol (a homopolymer where m=4), forexample, preferably n about 7 (when n=7, the IOB is 0.57).

Examples of commercial products of poly C₃-C₆ alkylene glycols includeUNIOL™ PB-500 and PB-700 (all products of NOF Corp.).

[(e₂) Ester of a Polyoxy C₃-C₆ Alkylene Glycol and at Least One FattyAcid]

Examples of an ester of a polyoxy C₃-C₆ alkylene glycol and at least onefatty acids include the polyoxy C₃-C₆ alkylene glycols mentioned for“(e₁) Polyoxy C₃-C₆ alkylene glycol” in which one or both OH ends havebeen esterified with fatty acids, i.e. monoesters and diesters.

Examples of fatty acids to be esterified in the ester of a polyoxy C₃-C₆alkylene glycol and at least one fatty acid include the fatty acidsmentioned for the “(a₁) Ester of a chain hydrocarbon tetraol and atleast one fatty acid”, and specifically these include saturated fattyacids and unsaturated fatty acids, with saturated fatty acids beingpreferred in consideration of the potential for degradation by oxidationand the like.

[(e₃) Ether of a Polyoxy C₃-C₆ Alkylene Glycol and at Least OneAliphatic Monohydric Alcohol]

Examples of an ether of a polyoxy C₃-C₆ alkylene glycols and at leastone aliphatic monohydric alcohol include the polyoxy C₃-C₆ alkyleneglycols mentioned for “(e₁) Polyoxy C₃-C₆ alkylene glycol” wherein oneor both OH ends have been etherified by an aliphatic monohydric alcohol,i.e. monoethers and diethers.

In an ether of a polyoxy C₃-C₆ alkylene glycol and at least onealiphatic monohydric alcohol, the aliphatic monohydric alcohol to beetherified may be an aliphatic monohydric alcohol among those mentionedfor “compound (B)”.

[(F) Chain Hydrocarbon]

Examples of chain hydrocarbons include (f₁) chain alkanes, such asstraight-chain alkanes and branched chain alkanes. Straight-chainalkanes with melting points of about 45° C. or less have up to about 22carbon atoms, and at a vapor pressure of 1 atmosphere and no greaterthan about 0.01 Pa at 25° C., the number of carbon atoms is 13 orgreater. Branched chain alkanes tend to have lower melting points thanchain alkanes, given the same number of carbon atoms. Branched chainalkanes may therefore include those with 22 and more carbon atoms, evenwith melting points of below about 45° C.

Examples of commercially available hydrocarbon products include PARLEAM6 (NOF Corp.).

In an absorbent article according to one embodiment of this disclosure,the blood slipping agent-containing region contains the aforementionedblood slipping agent.

In an absorbent article according to another embodiment of thisdisclosure, the blood slipping agent-containing region consists entirelyof the aforementioned blood slipping agent. Stated differently, the topsheet has a blood slipping agent-containing region consisting entirelyof a blood slipping agent, in the excretory opening contact region.

In an absorbent article according to another embodiment of thisdisclosure, the blood slipping agent-containing region comprises a bloodslipping agent-containing composition including the aforementioned bloodslipping agent and at least one other component. Stated differently, inan absorbent article according to another embodiment of this disclosure,the top sheet has, in the excretory opening contact region, a bloodslipping agent-containing region comprising a blood slippingagent-containing composition including the aforementioned blood slippingagent and at least one other component.

Such a blood slipping agent-containing composition will now bedescribed.

[Blood Slipping Agent-containing Composition]

The blood slipping agent-containing composition contains a bloodslipping agent and at least one other component.

The other component is not particularly restricted so long as it doesnot inhibit the effect of the present disclosure, and it may be any onecommonly employed in absorbent articles of the art, and especially topsheets.

Examples for the other component(s) include silicone oils, silicones,silicone-based resins and the like.

Examples for the other component(s) also include antioxidants, such asBHT (2,6-di-t-butyl-p-cresol), BHA (butylated hydroxyanisole) and propylgallate.

Further examples for the other component(s) include vitamins, such asnatural vitamins and synthetic vitamins. Examples of vitamins includewater-soluble vitamins, such as group B vitamins, including vitamin B₁,vitamin B₂, vitamin B₃, vitamin B₅, vitamin B₆, vitamin B₇, vitamin B₉and vitamin B₁₂, and vitamin C.

Other examples of vitamins include fat-soluble vitamins, such as group Avitamins, group D vitamins, group E vitamins and group K vitamins.

The derivatives of these vitamins are also included.

Examples for the other component(s) include amino acids, such asalanine, arginine, lysine, histidine, proline and hydroxyproline, andpeptides.

Other examples for the other component(s) include zeolite, such asnatural zeolite, examples of which include analcite, chabazite,heulandite, natrolite, stilbite and thomosonite, and synthetic zeolite.

Still other examples for the other component(s) include cholesterol,hyaluronic acid, lecithin and ceramide.

Yet other examples for the other component(s) include drugs, such asskin astringents, anti-pimple medications, anti-wrinkle agents,anti-cellulite agents, skin whiteners, antimicrobial agents andantifungal agents.

Examples of skin astringents include zinc oxide, aluminum sulfate,tannic acid and the like, and oil-soluble skin astringents, such asfat-soluble polyphenols. Fat-soluble polyphenols include naturalfat-soluble polyphenols, such as barley extract, otogiriso extract,white deadnettle extract, chamomilla extract, burdock extract, salviaextract, linden extract, common lime extract, white birch extract,common horsetail extract, sage extract, salvia extract, walnut (J. regiaL. var. orientalis) extract, hibiscus extract, loquat leaf extract,Miquel's linden extract, hop extract, common horse-chestnut extract andcoix seed extract.

Examples of anti-pimple medications include salicylic acid, benzoylperoxide, resorcinol, sulfur, erythromycin and zinc.

Examples of anti-wrinkle agents include lactic acid, salicylic acid,salicylic acid derivatives, glycolic acid, phytic acid, lipoic acid andlysophosphatidic acid.

Examples of anti-cellulite agents include xanthine compounds, such asaminophylline, caffeine, theophylline and theobromine.

Examples of skin whiteners include niacinamide, kojic acid, arbutin,glucosamine and its derivatives, phytosterol derivatives, and ascorbicacid and its derivatives, as well as mulberry extract and placentaextract.

Examples for the other component(s) also include anti-inflammatorycomponents, pH regulators, antimicrobial agents, humectants, aromatics,pigments, dyes, pigments and plant extracts. Examples ofanti-inflammatory components include naturally-derived anti-inflammatorydrugs, such as peony, golden grass, otogiriso, chamomile, licorice,peach leaf, Japanese mugwort and perilla extract, and syntheticanti-inflammatory drugs, such as allantoin and dipotassiumglycyrrhizinate.

Examples of pH regulators include those that keep the skin weaklyacidic, such as malic acid, succinic acid, citric acid, tartaric acidand lactic acid.

Titanium oxide is an example of a pigment.

The blood slipping agent-containing composition contains the bloodslipping agent and the one or more other components at preferably about50 to about 99 mass % and about 1 to about 50 mass %, respectively, morepreferably about 60 to about 99 mass % and about 1 to about 40 mass %,respectively, even more preferably about 70 to about 99 mass % and about1 to about 30 mass %, respectively, yet more preferably about 80 toabout 99 mass % and about 1 to about 20 mass %, respectively, even yetmore preferably about 90 to 99 mass % and about 1 to about 10 mass %,respectively, and even yet more preferably about 95 to 99 mass % andabout 1 to about 5 mass %, respectively. These ranges are from theviewpoint of the effect of the present disclosure.

The blood slipping agent-containing composition preferably contains asurfactant in no greater than the amount from hydrophilicizing treatmentof the top sheet or second sheet. More specifically, the blood slippingagent-containing composition contains a surfactant in a basis weightrange of preferably about 0.0 to about 1.0 g/m², more preferably about0.0 to about 0.8 g/m², even more preferably about 0.1 to about 0.5 g/m²,and yet more preferably about 0.1 to about 0.3 g/m².

This is because when the amount of surfactant is increased, menstrualblood will tend to be retained in the top sheet. The surfactant,incidentally, has no water holding percentage. This is because there isno layer of the substance to be measured, due to admixture with water.

The blood slipping agent-containing composition contains water in abasis weight range of preferably about 0.0 to about 1.0 g/m², morepreferably about 0.0 to about 0.8 g/m², even more preferably about 0.1to about 0.5 g/m², and yet more preferably about 0.1 to about 0.3 g/m².

Since water lowers the absorption performance of the absorbent article,the amount is preferably low.

Similar to the blood slipping agent, the blood slipping agent-containingcomposition, as a composition, has at 40° C., a kinematic viscosity ofpreferably about 0 to about 80 mm²/s, more preferably a kinematicviscosity of about 1 to about 70 mm²/s, even more preferably a kinematicviscosity of about 3 to about 60 mm²/s, yet more preferably a kinematicviscosity of about 5 to about 50 mm²/s, and even yet more preferably akinematic viscosity of about 7 to about 45 mm²/s.

If the kinematic viscosity of the blood slipping agent-containingcomposition exceeds 80 mm²/s, the viscosity will increase, and the bloodslipping agent composition may not slide down into the interior of theabsorbent article as easily with menstrual blood that has reached theskin contact surface of the top sheet.

When the blood slipping agent-containing composition contains acomponent that is miscible with the blood slipping agent, as at leastone other component, the other component preferably has a weight-averagemolecular weight of less than about 1000, and more preferably aweight-average molecular weight of less than about 900. This is because,if the weight-average molecular weight is about 1000 or higher, tack mayresult in the blood slipping agent-containing composition itself,tending to create a feeling of unpleasantness for the wearer. If theweight-average molecular weight increases, the viscosity of the bloodslipping agent-containing composition will tend to increase, and it willtherefore be difficult to lower the viscosity of the blood slippingagent composition by heating to a viscosity suitable for coating, and asa result, the blood slipping agent may need to be diluted with asolvent.

The blood slipping agent-containing composition, as a composition, has awater holding percentage of about 0.01 to about 4.0 mass %, preferablyit has a water holding percentage of about 0.02 to about 3.5 mass %,more preferably it has a water holding percentage of about 0.03 to about3.0 mass %, even more preferably it has a water holding percentage ofabout 0.04 to about 2.5 mass %, and yet more preferably it has a waterholding percentage of about 0.05 to about 2.0 mass %.

A low water holding percentage value will tend to lower the affinitybetween the blood slipping agent composition and menstrual blood, thusinhibiting it from sliding down into the interior of the absorbentarticle with menstrual blood that has reached the skin contact surfaceof the top sheet.

When the blood slipping agent-containing composition contains solidmatter, it is preferably removed by filtration for measurement of thekinematic viscosity and water holding percentage.

[Method of Producing Absorbent Article]

The method of producing an absorbent article according to one embodimentof this disclosure is one wherein an absorbent article includes aliquid-permeable top sheet, a liquid-impermeable back sheet, anabsorbent body between the top sheet and the back sheet, and optionallya second sheet between the top sheet and the absorbent body, the methodincluding a step in which a blood slipping agent or a blood slippingagent-containing composition containing a blood slipping agent is coatedonto the surface of the top sheet on which the clothing side surface isto be formed, to form a blood slipping agent-containing region on thetop sheet, after which the top sheet, optionally the second sheet, theabsorbent body and the back sheet are layered.

FIG. 5 is a diagram showing the production process for an absorbentarticle according to an embodiment of this disclosure.

Around the outer peripheral surface of the suction drum 101 rotating inthe machine direction MD there are formed recess shapes 103 at aprescribed pitch, as shapes for forming the absorbent body material 102.As the suction drum 101 rotates and the recess shapes 103 approach thematerial feeder 104, the absorbent body material 102 drawn by thesuction section 105 moves into the recess shapes 103, forming absorbentcores 107. The absorbent cores 107 move onto the carrier sheet 106 thatis advancing in the machine direction MD. The absorbent core 107 ispackaged with a core wrap (not shown) and embossed with an embossingroll 111, and then cut with a cutter 121 to form an absorbent body 3.

Next, the clothing side surface of the top sheet 2 that has been woundout from the top sheet roll 131 is coated with an adhesive from anadhesive coater 132, and then after coating a coating solution of theblood slipping agent 9 (or blood slipping agent-containing composition)from a coater 133, the clothing side surface of the top sheet 2 isbonded to the absorbent body 3 to form a multilayer article 134. Themultilayer article 134 (top sheet 2 and absorbent body 3) is thenembossed with an embossing roll 141.

Next, the back sheet 8 that has been reeled out from a back sheet roll151 is coated with an adhesive from the adhesive coater 152, and bondedto the multilayer article 134 to form a multilayer article 153. Theembossing roll 161 is then used for round embossing of the multilayerarticle 153 into the shape of an absorbent article, and is cut into theshape of an absorbent article with a cutter 171, to complete theabsorbent article 1.

The method of producing an absorbent article according to anotherembodiment of this disclosure is one wherein an absorbent articleincludes a liquid-permeable top sheet, an absorbent body, aliquid-impermeable back sheet and a second sheet between the top sheetand the absorbent body, the method including a step in which a bloodslipping agent or a blood slipping agent-containing compositioncontaining a blood slipping agent is coated onto the surface of thesecond sheet on which the skin side surface is to be formed, to form ablood slipping agent-containing region on the second sheet, after whichthe top sheet, the second sheet, the absorbent body and the back sheetare layered.

FIG. 6 is a diagram showing the production process for an absorbentarticle according to another embodiment of this disclosure.

In FIG. 6, the steps up to production of the absorbent body 3 are thesame as in FIG. 5 and will not be explained again.

The skin side surface of the second sheet 12 that has been reeled outfrom the second sheet roll 232 is coated with a coating solution of theblood slipping agent 9 (or blood slipping agent-containing composition)from the coater 233, and then the skin side surface of the second sheet12 is layered with the clothing side surface of the top sheet 2 that hasbeen reeled out from the top sheet roll 231, forming a multilayerarticle 234. The clothing side surface of the multilayer article 234(i.e. the clothing side surface of the second sheet 12) is coated withan adhesive from the adhesive coater 235, and the multilayer article 234and absorbent body 3 are layered to form a multilayer article 234. Themultilayer article 234 (top sheet 2, second sheet 12 and absorbent body3) is then embossed with an embossing roll 241.

Next, the back sheet 8 that has been reeled out from a back sheet roll251 is coated with an adhesive from an adhesive coater 252, and the backsheet 8 and multilayer article 234 are layered to form a multilayerarticle 253. The embossing roll 261 is then used for round embossing ofthe multilayer article 253 into the shape of an absorbent article, andis cut into the shape of an absorbent article with a cutter 271, tocomplete the absorbent article 1.

The blood slipping agent or blood slipping agent-containing compositionmay, if desired, be applied as a coating solution containing a volatilesolvent, such as an alcohol-based solvent, ester-based solvent oraromatic solvent. If the coating solution includes a volatile solvent,the viscosity of the coating solution containing the blood slippingagent or blood slipping agent-containing composition will be lowered,thereby allowing the application steps to be simplified, facilitatingapplication and making heating during application unnecessary.

There are no particular restrictions on the method of applying the bloodslipping agent or blood slipping agent-containing composition, or thecoating solution containing it, and if necessary the blood slippingagent or blood slipping agent-containing composition or the coatingsolution containing it may be heated, and a coating applicator, forexample a non-contact coater, such as a spiral coater, curtain coater,spray coater or dip coater, or a contact coater, may be used forapplication of the blood slipping agent or blood slippingagent-containing composition or the coating solution containing it. Thecoating applicator is preferably a non-contact coater, from theviewpoint of uniformly dispersing the droplet or particulate modifyingagent throughout, and from the viewpoint of not causing damage in thematerial.

The blood slipping agent or blood slipping agent-containing composition,or the coating solution containing it, may be coated directly, if it isa liquid at room temperature, or it may be heated to lower theviscosity, and when it is a solid at room temperature, it may be heatedto liquefaction and coated from a control seam HMA (Hot Melt Adhesive)gun. By increasing the air pressure of the control seam HMA gun, it ispossible to apply the blood slipping agent or blood slippingagent-containing composition as fine particulates.

The coating amount of the blood slipping agent or blood slippingagent-containing composition may be adjusted, for example, by increasingor reducing the amount of application from the control seam HMA gun.

Any liquid-permeable top sheet that is commonly used in the art may beemployed without any particular restrictions, and for example, it may bea sheet-like material having a structure that allows permeation ofliquids, such as a porous film, woven fabric, nonwoven fabric or thelike. The fibers composing such a woven fabric or nonwoven fabric may benatural fibers or chemical fibers, with examples of natural fibersincluding cellulose, such as ground pulp and cotton, and examples ofchemical fibers including regenerated cellulose, such as rayon andfibril rayon, semi-synthetic cellulose, such as acetate and triacetate,thermoplastic hydrophobic chemical fibers, and hydrophilicizedthermoplastic hydrophobic chemical fibers.

Examples of thermoplastic hydrophobic chemical fibers includepolyethylene (PE), polypropylene (PP) and polyethylene terephthalate(PET) monofilaments, and fibers including PE and PP graft polymers.

Examples of nonwoven fabrics include air-through nonwoven fabrics,spunbond nonwoven fabrics, point bond nonwoven fabrics, spunlacenonwoven fabrics, needle punching nonwoven fabrics and meltblownnonwoven fabrics, as well as combinations thereof (such as SMS and thelike).

Liquid-impermeable back sheets include films comprising PE and PP,air-permeable resin films, air-permeable resin films bonded to spunbondor spunlace nonwoven fabrics, and multilayer nonwoven fabrics, such asSMS. In consideration of flexibility of the absorbent article, alow-density polyethylene (LDPE) film with a basis weight of about 15-30g/m², for example, is preferred.

The second sheet may be any of the same examples as for theliquid-permeable top sheet.

The first example of the absorbent body is one having an absorbent corecovered with a core wrap.

Examples of components for the absorbent core include hydrophilicfibers, including cellulose, such as ground pulp or cotton, regeneratedcellulose, such as rayon or fibril rayon, semi-synthetic cellulose, suchas acetate or triacetate, particulate polymers, filamentous polymers,thermoplastic hydrophobic chemical fibers, and hydrophilicizedthermoplastic hydrophobic chemical fibers, as well as combinationsthereof. The component of the absorbent core may also be a superabsorbent polymer, such as granules of a sodium acrylate copolymer orthe like.

The core wrap is not particularly restricted so long as it is asubstance that is liquid-permeable and with a barrier property that doesnot allow permeation of the polymer absorber, and it may be a wovenfabric or nonwoven fabric, for example. The woven fabric or nonwovenfabric may be made of a natural fiber, chemical fiber, tissue, or thelike.

A second example of the absorbent body is one formed from an absorbingsheet or polymer sheet, with a thickness of preferably about 0.3-5.0 mm.The absorbing sheet or polymer sheet may usually be used without anyparticular restrictions so long as it is one that can be used in anabsorbent article, such as a sanitary napkin.

The side sheet may be any of the same examples as for theliquid-permeable top sheet.

The flap can be formed from a side sheet and a liquid-impermeable backsheet, and optionally it may have a reinforcing sheet, such as paper,between them.

When the liquid-permeable top sheet is formed from a nonwoven fabric orwoven fabric, the blood slipping agent or blood slippingagent-containing composition preferably does not obstruct the voidsbetween the fibers of the nonwoven fabric or woven fabric, and forexample, the blood slipping agent or blood slipping agent-containingcomposition may be attached as droplets or particulates on the surfaceof the nonwoven fabric or woven fabric fibers, or it may be covering thesurfaces of the fibers.

On the other hand, when the liquid-permeable top sheet is formed of aporous film, the blood slipping agent or blood slipping agent-containingcomposition preferably does not occlude the pores of the porous film,and the blood slipping agent or the blood slipping agent-containingcomposition may either be attached to the surface of the porous film asdroplets or particulates, or it may cover the surface of the filmwithout occluding the pores. This is because if the blood slipping agentor blood slipping agent-containing composition obstructs the pores inthe porous film, migration of the absorbed liquid into the absorbentbody may be inhibited.

Furthermore, in order for the blood slipping agent or blood slippingagent-containing composition to slip down together with the absorbedmenstrual blood, it preferably has a large surface area, and a bloodslipping agent or blood slipping agent-containing composition present asdroplets or particulates preferably has a small droplet/particlediameter.

The absorbent article according to another embodiment of this disclosurehas an absorbent body comprising a blood slipping agent or a bloodslipping agent-containing composition.

When the material coated with the blood slipping agent or blood slippingagent-containing composition, for example, a top sheet, is a nonwovenfabric or woven fabric formed from a synthetic resin, or a porous filmor the like, it is preferably subjected to hydrophilicizing treatment.The hydrophilicizing treatment may involve coating the surfaces of thefibers of the nonwoven fabric or woven fabric or the surface of theporous film with a hydrophilic agent, or mixing a hydrophilic agent withthe synthetic resin used as the starting material for the nonwovenfabric or woven fabric or porous film.

This is because, if the material before coating of the blood slippingagent or blood slipping agent-containing composition is hydrophilic,there will be lipophilic regions due to the blood slipping agent, andhydrophilic regions due to the hydrophilic agent, that are sparselydispersed on the top sheet, which will allow the blood slipping agent orblood slipping agent-containing composition to exhibit slippingperformance and will facilitate rapid migration of menstrual blood intothe absorbent body.

The blood slipping agent or blood slipping agent-containing compositionalso has an effect as a lubricant. Thus, when the top sheet is anonwoven fabric or woven fabric, the blood slipping agent or bloodslipping agent-containing composition reduces friction between thefibers and improves the flexibility. When the top sheet is a resin film,the blood slipping agent or blood slipping agent-containing compositioncan reduce friction between the top sheet and the skin.

An absorbent article according to a preferred embodiment of thisdisclosure is one that is intended for absorption of blood, such as asanitary napkin or panty liner.

The absorbent article of this disclosure differs from known absorbentarticles containing skin care compositions, lotion compositions and thelike, in that it does not need components, such as emollients orimmobilizing agents, and therefore the absorbent article according toone embodiment of this disclosure does not contain an emollient and/orimmobilizing agent.

EXAMPLES

The present disclosure will now be explained in fuller detail byexamples, with the understanding that it is not meant to be limited tothe examples.

Example 1

[Evaluation of Rewetting Rate and Absorbent Body Migration Rate]

A commercially available sanitary napkin having the shape shown in FIG.1 (not coated with a blood slipping agent) was prepared. The sanitarynapkin was formed from a top sheet, formed of a hydrophilicagent-treated air-through nonwoven fabric (composite fiber composed ofpolyester and polyethylene terephthalate, basis weight: 35 g/m²), asecond sheet, formed of an air-through nonwoven fabric (composite fibercomposed of polyester and polyethylene terephthalate, basis weight: 30g/m²), an absorbent body comprising pulp (basis weight: 150 to 450 g/m²,increased at the center section), an acrylic super-absorbent polymer(basis weight: 15 g/m²) and tissue as a core wrap, a water-repellentagent-treated side sheet, and a back sheet composed of a polyethylenefilm.

The blood slipping agents used for testing are listed below.

[(a₁) Ester of Straight-chain Hydrocarbon Tetraol and at Least One FattyAcid]

-   -   UNISTAR H-408BRS, product of NOF Corp.

Pentaerythritol tetra(2-ethylhexanoate), weight-average molecularweight: approximately 640

-   -   UNISTAR H-2408BRS-22, product of NOF Corp.

Mixture of pentaerythritol tetra(2-ethylhexanoate) and neopentylglycoldi(2-ethylhexanoate) (58:42 as weight ratio), weight-average molecularweight: approximately 520

[(a₂) Ester of Straight-chain Hydrocarbon Triol and at Least One FattyAcid]

-   -   Cetiol SB45DEO, Cognis Japan

Glycerin and fatty acid triester, with oleic acid or stearylic acid asthe fatty acid.

-   -   SOY42, product of NOF Corp.

Glycerin and fatty acid triester with C₁₄ fatty acid:C₁₆ fatty acid:C₁₈fatty acid:C₂₀ fatty acid (including both saturated fatty acids andunsaturated fatty acids) at a mass ratio of about 0.2:11:88:0.8,weight-average molecular weight: 880

-   -   Tri-C2L oil fatty acid glyceride, product of NOF Corp.

Glycerin and fatty acid triester with C₈ fatty acid:C₁₀ fatty acid:C₁₂fatty acid at a weight ratio of about 37:7:56, weight-average molecularweight: approximately 570

-   -   Tri-CL oil fatty acid glyceride, product of NOF Corp.

Glycerin and fatty acid triester with C₈ fatty acid:C₁₂ fatty acid at aweight ratio of about 44:56, weight-average molecular weight:approximately 570

-   -   PANACET 810s, product of NOF Corp.

Glycerin and fatty acid triester with C₈ fatty acid:C₁₀ fatty acid at amass ratio of about 85:15, weight-average molecular weight:approximately 480

-   -   PANACET 800, product of NOF Corp.

Glycerin and fatty acid triester with octanoic acid (C₈) as the entirefatty acid portion, weight-average molecular weight: approximately 470

-   -   PANACET 800B, product of NOF Corp.

Glycerin and fatty acid triester with 2-ethylhexanoic acid (C₈) as theentire fatty acid portion, weight-average molecular weight:approximately 470

-   -   NA36, product of NOF Corp.

Glycerin and fatty acid triester with C₁₆ fatty acid:C₁₈ fatty acid:C₂₀fatty acid (including both saturated fatty acids and unsaturated fattyacids) at a mass ratio of about 5:92:3, weight-average molecular weight:approximately 880

-   -   Tri-coconut fatty acid glyceride, product of NOF Corp.

Glycerin and fatty acid triester with C₈ fatty acid:C₁₀ fatty acid:C₁₂fatty acid:C₁₄ fatty acid:C₁₆ fatty acid (including both saturated fattyacids and unsaturated fatty acids) at a mass ratio of about 4:8:60:25:3,weight-average molecular weight: 670

-   -   Caprylic acid diglyceride, product of NOF Corp.

Glycerin and fatty acid diester with octanoic acid as the fatty acid,weight-average molecular weight: approximately 340

[(a₃) Ester of a Chain Hydrocarbon Diol and at Least One Fatty Acid]

-   -   UNISTAR H-208BRS, product of NOF Corp.

Neopentyl glycol di(2-ethylhexanoate), weight-average molecular weight:approximately 360

-   -   COMPOL BL, product of NOF Corp.

Dodecanoic acid (C₁₂) monoester of butylene glycol, weight-averagemolecular weight: approximately 270

-   -   COMPOL BS, product of NOF Corp.

Octadecanoic acid (C₁₈) monoester of butylene glycol, weight-averagemolecular weight: approximately 350

[(c₂) Ester of a Chain Hydrocarbon Tricarboxylic Acid, Hydroxy Acid,Alkoxy Acid or Oxoacid with 3 Carboxyl Groups, and at Least OneAliphatic Monohydric Alcohol]

-   -   Tributyl O-acetylcitrate, product of Tokyo Kasei Kogyo Co., Ltd.

Weight-average molecular weight: approximately 400

-   -   Tributyl citrate, product of Tokyo Kasei Kogyo Co., Ltd.

Weight-average molecular weight: approximately 360

[(c₃) Ester of a Chain Hydrocarbon Dicarboxylic Acid, Hydroxy Acid,Alkoxy Acid or Oxoacid with 2 Carboxyl Groups, and at Least OneAliphatic Monohydric Alcohol]

-   -   Dioctyl adipate, product of Wako Pure Chemical Industries, Ltd.

Weight-average molecular weight: approximately 380

[(d₃) Ester of a Fatty Acid and an Aliphatic Monohydric Alcohol]

-   -   ELECTOL WE20, product of NOF Corp.

Ester of dodecanoic acid (C₁₂) and dodecyl alcohol (C12), weight-averagemolecular weight: approximately 360

-   -   ELECTOL WE40, product of NOF Corp.

Ester of tetradecanoic acid (C₁₄) and dodecyl alcohol (C₁₂),weight-average molecular weight: approximately 390

[(e₁) Polyoxy C₃-C₆ Alkylene Glycol]

-   -   UNIOL PB500, product of NOF Corp.

Polybutylene glycol, weight-average molecular weight: approximately 500

-   -   UNIOL PB700, product of NOF Corp.

Polyoxybutylene polyoxypropylene glycol, weight-average molecularweight: approximately 700

[(f₁) Chain Alkane]

-   -   PARLEAM 6, product of NOF Corp.

Branched chain hydrocarbon, produced by copolymerization of liquidisoparaffin, isobutene and n-butene followed by hydrogen addition,polymerization degree: approximately 5-10, weight-average molecularweight: approximately 330

[Other Materials]

-   -   NA50, product of NOF Corp.

Glycerin and fatty acid triester obtained by addition of hydrogen toNA36 for reduced proportion of double bonds from unsaturated fatty acidstarting material, weight-average molecular weight: approximately 880

-   -   (Caprylic acid/capric acid) monoglyceride, product of NOF Corp.

Glycerin and fatty acid monoester, with octanoic acid (C₈) and decanoicacid (C₁₀) at a mass ratio of about 85:15, weight-average molecularweight: approximately 220

-   -   Monomuls 90-L2 lauric acid monoglyceride, product of Cognis        Japan    -   Isopropyl citrate, product of Tokyo Kasei Kogyo Co., Ltd.

Weight-average molecular weight: approximately 230

-   -   Diisostearyl malate Weight-average molecular weight:        approximately 640    -   UNIOL PB1000R, product of NOF Corp.

Polybutylene glycol, weight-average molecular weight: approximately1,000

-   -   UNIOL D-250, product of NOF Corp.

Polypropylene glycol, weight-average molecular weight: approximately 250

-   -   UNIOL D-400, product of NOF Corp.

Polypropylene glycol, weight-average molecular weight: approximately 400

-   -   UNIOL D-700, product of NOF Corp.

Polypropylene glycol, weight-average molecular weight: approximately 700

-   -   UNIOL D-1000, product of NOF Corp.

Polypropylene glycol, weight-average molecular weight: approximately1,000

-   -   UNIOL D-1200, product of NOF Corp.

Polypropylene glycol, weight-average molecular weight: approximately1,160

-   -   UNIOL D-2000, product of NOF Corp.

Polypropylene glycol, weight-average molecular weight: approximately2,030

-   -   UNIOL D-3000, product of NOF Corp.

Polypropylene glycol, weight-average molecular weight: approximately3,000

-   -   UNIOL D-4000, product of NOF Corp.

Polypropylene glycol, weight-average molecular weight: approximately4,000

-   -   PEG1500, product of NOF Corp.

Polyethylene glycol, weight-average molecular weight: approximately1,500-1,600

-   -   WILBRITE cp9, product of NOF Corp.

Polybutylene glycol compound with OH groups at both ends esterified byhexadecanoic acid (C₁₆), weight-average molecular weight: approximately1,150

-   -   UNILUBE MS-70K, product of NOF Corp.

Stearyl ether of polypropylene glycol, approximately 15 repeating units,weight-average molecular weight: approximately 1,140

-   -   NONION S-6, product of NOF Corp.

Polyoxyethylene monostearate, approximately 7 repeating units,weight-average molecular weight: approximately 880

-   -   UNILUBE 5TP-300 KB

Polyoxyethylene polyoxypropylene pentaerythritol ether, produced byaddition of 5 mol of ethylene oxide and 65 mol of propylene oxide to 1mol of pentaerythritol, weight-average molecular weight: 4,130

-   -   WILBRITE s753, product of NOF Corp.

Polyoxyethylene polyoxypropylene polyoxybutylene glycerin,weight-average molecular weight: approximately 960

-   -   UNIOL TG-330, product of NOF Corp.

Glyceryl ether of polypropylene glycol, approximately 6 repeating units,weight-average molecular weight: approximately 330

-   -   UNIOL TG-1000, product of NOF Corp.

Glyceryl ether of polypropylene glycol, approximately 16 repeatingunits, weight-average molecular weight: approximately 1,000

-   -   UNIOL TG-3000, product of NOF Corp.

Glyceryl ether of polypropylene glycol, approximately 16 repeatingunits, weight-average molecular weight: approximately 3,000

-   -   UNIOL TG-4000, product of NOF Corp.

Glyceryl ether of polypropylene glycol, approximately 16 repeatingunits, weight-average molecular weight: approximately 4,000

-   -   UNILUBE DGP-700, product of NOF Corp.

Diglyceryl ether of polypropylene glycol, approximately 9 repeatingunits, weight-average molecular weight: approximately 700

-   -   UNIOX HC60, product of NOF Corp.

Polyoxyethylene hydrogenated castor oil, weight-average molecularweight: approximately 3,570

-   -   Vaseline, product of Cognis Japan

Petroleum-derived hydrocarbon, semi-solid

The kinematic viscosities, water holding percentages, weight-averagemolecular weights, IOBs and melting points of the samples are shown inTable 2.

For the melting point, “<45” indicates a melting point of below 45° C.

Almost the entire skin contact surface of the top sheet of the sanitarynapkin was coated with the aforementioned blood slipping agent. Eachblood slipping agent was used directly, when the blood slipping agentwas liquid at room temperature, or when the blood slipping agent wassolid at room temperature it was heated to a temperature of its meltingpoint +20° C., and then a control seam HMA gun was used for atomizationof each blood slipping agent and coating onto the skin contact surfaceof the top sheet to a basis weight of about 5 g/m².

FIG. 7 is an electron micrograph of the skin contact surface of a topsheet in a sanitary napkin (No. 1-5) wherein the top sheet comprisestri-C2L oil fatty acid glycerides. As clearly seen in FIG. 7, thetri-C2L oil fatty acid glycerides are present on the fiber surfaces asfine particulates.

[Test Methods]

An acrylic board with an opened hole (200 mm×100 mm, 125 g, with a 40mm×10 mm hole opened at the center) was placed on a top sheet comprisingeach blood slipping agent, and 3.0 g of horse EDTA blood at 37±1° C.(obtained by adding ethylenediaminetetraacetic acid (hereunder, “EDTA”)to horse blood to prevent coagulation) was dropped through the holeusing a pipette (once), and after 1 minute, 3.0 g of horse EDTA blood at37±1° C. was again added dropwise through the acrylic board hole with apipette (twice).

After the second dropping of blood, the acrylic board was immediatelyremoved and 10 sheets of filter paper (Qualitative filter paper No. 2,product of Advantech Toyo, Inc., 50 mm×35 mm) (total weight of 10 filtersheets: FW₀ (g)) were placed on the location where the blood had beendropped, and then a weight was placed thereover at a pressure of 30g/cm². After 1 minute, the filter paper was removed, the total weightFW₁ (g) of the 10 tested filter sheets was measured, and the “rewettingrate” was calculated by the following formula.Rewetting rate (mass %)=100×[FW ₁ (g)−FW ₀ (g)]/6.0 (g)

In addition to the rewetting rate evaluation, the “absorbent bodymigration rate” was also measured as the time until migration of bloodfrom the top sheet to the absorbent body after the second dropping ofblood. The absorbent body migration rate is the time from introducingthe blood onto the top sheet, until the redness of the blood could beseen on the surface and in the interior of the top sheet.

The results for the rewetting rate and absorbent body migration rate areshown below in Table 2.

The whiteness of the skin contact surface of the top sheet (TS) afterthe absorbent body migration rate test was visually evaluated on thefollowing scale.

VG (Very Good): Virtually no redness of blood remaining, and no cleardelineation between areas with and without blood.

G (Good): Slight redness of blood remaining, but difficult todiscriminate between areas with and without blood.

F (Fair): Slight redness of blood remaining, areas with blooddiscernible.

P (Poor): Redness of blood completely remaining.

The tack on the skin contact surface of the top sheet was also measuredat 35° C., and evaluated on the following scale.

G: No tack

F: Slight tack

P: Tack

The results are summarized in Table 2 below.

TABLE 2 Kinematic Absorbent viscosity Water holding Melting body Bloodslipping (mm²/s, percentage Wt.-average point Rewetting migration TS No.agent 40° C.) (mass %) mol. wt. IOB (° C.) rate (%) rate (sec) whitenessTack 1-1 H-408BRS 45 0.7 640 0.13 <−5 1.2 3 VG G 1-2 H-2408BRS-22 22 0.8520 0.18 <−5 2.0 3 VG G 1-3 Cetiol SB45DEO 0.16 44 7.0 6 VG 1-4 SOY42880 0.16 43 5.8 8 VG G 1-5 Tri-C2L oil fatty 20 <1.0 570 0.27 37 0.3 3VG G acid glyceride 1-6 Tri-CL oil fatty 15 <1.0 570 0.28 38 1.7 3 VG Gacid glyceride 1-7 PANACET 810s  9 0.3 480 0.32 −5 2.8 3 VG G 1-8PANACET 800 15 0.5 470 0.33 −5 0.3 3 VG G 1-9 PANACET 800B 20 <1.0 4700.33 −5 2.0 3 VG G 1-10 NA36 40 <1.0 880 0.16 37 3.9 5 VG G 1-11Tri-coconut oil 25 <1.0 670 0.28 30 4.3 5 VG G fatty acid glyceride 1-12Caprylic acid 25 2.7 340 0.58 <45 4.2 9 G G diglyceride 1-13 UNISTARH-208BRS  8 0.7 360 0.24 <−5 2.0 5 VG G 1-14 COMPOL BL 10 1.6 270 0.50 22.0 5 G G 1-15 COMPOL BS 35 0.3 350 0.36 37 7.9 9 G G 1-16 Tributyl 150.9 400 0.60 <45 6.2 8 VG G O-acetylcitrate 1-17 Tributyl citrate 12 0.6360 0.78 <45 3.0 6 G G 1-18 Dioctyl adipate  7 0.4 380 0.27 <45 1.7 6 VGG 1-19 ELECTOL WE20 10 0.3 360 0.13 29 1.8 5 VG G 1-20 ELECTOL WE40 150.5 390 0.12 37 1.8 4 VG G 1-21 UNIOL PB500 40 3.6 500 0.44 <45 4.5 4 GG 1-22 UNIOL PB700 50 2.3 700 0.49 −5 2.8 5 G G 1-23 PARLEAM 6  5 0.06330 0.00 −5 6.0 8 VG G 1-24 NA50     80<< —* 880 0.18 52 15.5 60  P G1-25 (Caprylic acid/ 70 4.0<< 220 1.15 <45 4.0 4 P G Capric acid)monoglyceride 1-26 90-L2 Lauric     80<< 4.0<< <1,000 0.87 58 6.2 7 P Gacid monoglyceride 1-27 Isopropyl citrate 120  4.0<< 230 1.56 <45 12.2 5G F 1-28 Diisostearyl malate 450  4.0<< 640 0.28 <45 5.5 8 F F 1-29UNIOL PB1000R 70 5.5 1000 0.40 <45 4.0 4 G F 1-30 UNIOL D-250 20 4.0<<250 <45 — — P G 1-31 UNIOL D-400 30 4.0<< 400 0.76 <45 8.7 40  P G 1-32UNIOL D-700 50 34.6 700 0.58 <45 7.5 — F G 1-33 UNIOL D-1000 70 26.71,000 0.51 <45 6.8 15  F F 1-34 UNIOL D-1200 90 16.2 1,160 0.48 <45 0.511  F F 1-35 UNIOL D-2000 160  2,030 <45 — — F P 1-36 UNIOL D-3000 0.63,000 0.39 <45 1.7 10  F P 1-37 UNIOL D-4000 450  0.5 4,000 0.38 <45 1.07 G P 1-38 PEG1500 120  4.0<< 1,500-1,600 0.78 40 11.0 38  P P 1-39WILBRITE CP9 120  0.6 1,150 0.21 35 1.4 3 G P 1-40 UNILUBE MS-70K 50 2.81,140 0.30 <−10 6.7 3 G F 1-41 NONION S-6 65 4.0<< 880 0.44 37 8.4 7 P G1-42 UNILUBE 5TP-300KB 310  3.9 4,130 0.39 <45 2.0 6 G P 1-43 WILBRITEs753 120  27.3 960 0.67 −5 9.3 9 F F 1-44 UNIOL TG-330 30 330 1.27 <45 —— — G 1-45 UNIOL TG-1000 100  21.2 1,000 0.61 <45 14.2 7 G G 1-46 UNIOLTG-3000 230  4.3 3,000 0.42 <45 0.8 6 G P 1-47 UNIOL TG-4000 300  2.44,000 0.40 <45 2.0 6 G P 1-48 UNILUBE DGP-700 200  4.0<< 700 0.91 <0 8.010  F F 1-49 UNIOX HC60 1150  3,570 0.46 33 14.6 46  P P 1-50 Vaseline    80<< 0.0 <1,000 0.00 55 9.7 10  F P 1-51 None — — — — — 22.7 60< P G*High viscosity, unmeasurable.

In the absence of a blood slipping agent, the rewetting rate was 22.7%and the absorbent body migration rate was greater than 60 seconds, butthe glycerin and fatty acid triesters all produced rewetting rates of nogreater than 7.0% and absorbent body migration rates of no longer than 8seconds, and therefore significantly improved the absorptionperformance.

Similarly, it was found that the absorption performance is greatlyimproved with a blood slipping agent having a kinematic viscosity ofabout 0.01 to 80 mm²/s at 40° C., a water holding percentage of about0.01 to about 4.0 mass %, and a weight-average molecular weight of lessthan about 1,000.

Next, several volunteer participants were asked to wear sanitary napkinsNos. 1-1 to 1-51, and the obtained responses indicated that with thesanitary napkins comprising blood slipping agent Nos. 1-1 to 1-23, thetop sheets had no sticky feel and the top sheets were smooth, even afterabsorption of menstrual blood.

Also, with sanitary napkins that comprised blood slipping agent Nos.1-11, 1-13, 1-16, 1-18 to 1-20 and 1-23, the skin contact surfaces ofthe top sheets after absorption of menstrual blood was not reddened bythe blood and the unpleasantness was minimal.

Also, the top sheet was removed from a commercially available sanitarynapkin having the shape shown in FIG. 1 (not coated with a bloodslipping agent), and the clothing side surface thereof was coated withthe aforementioned blood slipping agent in the region indicated inFIG. 1. The blood slipping agent was coated so that the blood slippingagent-containing region contained the blood slipping agent at a basisweight of about 5 g/m², using a control seam HMA gun, with heating to atemperature of the melting point +20° C. as necessary. Upon visuallyconfirming the top sheet coated with the blood slipping agent, the basisweight of the blood slipping agent on the clothing side surface (coatedside) was found to be greater than the basis weight of the bloodslipping agent on the skin side surface (non-coated side).

Next, the top sheet was rebonded to the absorbent body to preparesanitary napkins No. 1′-1 (H-408BRS) to No. 1′-23 (PARLEAM 6).

Sanitary napkins No. 1′-1 (H-408BRS) to No. 1′-23 (PARLEAM 6) wereprepared in this manner. The sanitary napkins No. 1′-1 and No. 1-1 wereidentical in that the blood slipping agent was H-408BRS, but thedistribution of the blood slipping agent in the thickness direction ofthe absorbent article was different. This also applies to the othersanitary napkins.

When the sanitary napkins produced for No. 1′-1 to 1′-23 were worn byseveral volunteer participants, the sanitary napkins of No. 1′-1 to1′-23 generally had equivalent performance to No. 1-1 to 1-23, and theresponses received indicated that after menstrual blood had beenabsorbed, the menstrual blood was rapidly absorbed into the absorbentbody within the excretory opening contact region.

This equivalent performance is partially attributed to the bloodslipping agent on the clothing side surface of the top sheet havingmigrated onto the skin side surface by pressure applied onto thesanitary napkin by daily activities of the wearer.

Example 2

[Surface Residue Rate of Menstrual Blood on Top Sheet with Ridge-furrowStructure]

The surface residue rate of menstrual blood on a top sheet with aridge-furrow structure was evaluated.

There were prepared a top sheet, formed of a hydrophilic agent-treatedair-through nonwoven fabric (composite fiber composed of polyester andpolyethylene terephthalate, basis weight: 35 g/m²), a second sheet,formed of an air-through nonwoven fabric (composite fiber composed ofpolyester and polyethylene terephthalate, basis weight: 30 g/m²), anabsorbent body comprising pulp (basis weight: 150 to 450 g/m², increasedat the center section), an acrylic super-absorbent polymer (basisweight: 15 g/m²) and tissue as a core wrap, a water-repellentagent-treated side sheet, and a back sheet composed of a polyethylenefilm.

The top sheet was a top sheet produced by the method described inJapanese Unexamined Patent Publication No. 2008-2034, having aridge-furrow structure, with a ridge thickness of approximately 1.5 mmand a furrow thickness of approximately 0.4 mm, the pitch of theridge-furrow structure (ridge width+furrow width) was approximately 4mm, and open holes were formed in the furrows at an open area ofapproximately 15%.

UNISTAR H-408BRS (product of NOF Corp., tetraester of pentaerythritoland fatty acid) was selected as the blood slipping agent, and it wascoated onto the skin contact surface (ridge-furrow side) of the topsheet from a control seam HMA gun at room temperature, to a basis weightof 5.0 g/m². With an electron microscope it was confirmed that theH-408BRS was adhering onto the fiber surfaces as fine particulates.

A back sheet, an absorbent body, a second sheet, and a top sheet withthe ridge-furrow side facing upward, were stacked in that order to formsanitary napkin No. 2-1.

Sanitary napkins No. 2-2 to No. 2-40 were produced, changing the bloodslipping agent from UNISTAR H-408BRS to the ones listed in Table 3. Eachblood slipping agent was used directly, when it was liquid at roomtemperature, or when the blood slipping agent was solid at roomtemperature it was heated to its melting point of +20° C., and then acontrol seam HMA gun was used for atomization of the blood slippingagent and coating onto the skin contact surface of the top sheet to abasis weight of about 5 g/m².

The blood slipping agent was coated onto essentially the entire skincontact surface of the top sheet, and on both the ridges and furrows.

[Test Methods]

After measuring the weight: W₂ (g) of the top sheet (the weight of thetop sheet before the test), an acrylic board with an opened hole (200mm×100 mm, 125 g, with a 40 mm×10 mm hole opened at the center) wasplaced on the top sheet, at the center section in the lengthwisedirection and widthwise direction of the absorbent article, and 4.0 g ofhorse EDTA blood at 37±1° C. (obtained by addingethylenediaminetetraacetic acid (hereunder, “EDTA”) to horse blood toprevent coagulation) was dropped through the hole using a pipette.

After dropping the horse EDTA blood, the acrylic board was immediatelyremoved, the top sheet was taken off, the mass W₃ (g) (mass of the topsheet after the test) was measured and the “surface residue rate A (mass%)” was calculated by the following formula.Surface residue rate (mass %)=100×[W ₃ (g)−W ₂ (g)]/4.0 (g)

The results are shown in Table 3 below.

TABLE 3 Surface residue No. Blood slipping agent rate (mass %) 2-1H-408BRS 0.8 2-2 H-2408BRS-22 0.8 2-3 PANACET 810s 0.8 2-4 PANACET 8001.8 2-5 Caprylic acid diglyceride 1.0 2-6 UNISTAR H-208BRS 0.5 2-7COMPOL BL 1.3 2-8 COMPOL BS 2.5 2-9 Tributyl O-acetylcitrate 0.5 2-10Tributyl citrate 1.8 2-11 Dioctyl adipate 1.5 2-12 ELECTOL WE20 0.5 2-13ELECTOL WE40 2.3 2-14 UNIOL PB500 2.5 2-15 UNIOL PB700 1.3 2-16 PARLEAM6 2.0 2-17 NA50 4.3 2-18 (Caprylic acid/Capric acid) monoglyceride 5.02-19 90-L2 Lauric acid monoglyceride 5.0 2-20 Isopropyl citrate 4.8 2-21Diisostearyl malate 3.3 2-22 UNIOL PB1000R 2.5 2-23 UNIOL D-250 3.8 2-24UNIOL D-400 4.8 2-25 UNIOL D-700 4.8 2-26 UNIOL D-1000 3.8 2-27 UNIOLD-1200 3.0 2-28 UNIOL D-3000 3.0 2-29 UNIOL D-4000 2.5 2-30 PEG1500 5.52-31 WILBRITE CP9 6.8 2-32 UNILUBE MS-70K 1.5 2-33 UNILUBE 5TP-300KB 2.02-34 WILBRITE s753 3.5 2-35 UNIOL TG-1000 3.5 2-36 UNIOL TG-3000 1.02-37 UNIOL TG-4000 2.0 2-38 UNILUBE DGP-700 3.5 2-39 Vaseline 4.0 2-40None 7.5

With sanitary napkin No. 2-40, which had no blood slipping agent, thesurface residue rate was 7.5 mass %, but with sanitary napkins No. 2-1to No. 2-16 wherein the kinematic viscosity and water holding percentagewere within the prescribed ranges, the surface residue rate was 2.5 mass% or lower.

With sanitary napkins No. 2-1 to No. 2-16, it was observed that thehorse EDTA blood that was dropped onto the ridges of the top sheetslipped down from the ridges into the furrows, and was rapidly absorbedfrom the furrows into the absorbent body. However, with sanitary napkinNo. 2-40 which had no blood slipping agent, the dropped horse EDTA blooddid not slip down into the furrows but slowly dripped down into thefurrows, most of it remaining on the ridges of the top sheet. Also, withthe absorbent articles with high water holding percentage, as with No.2-25, for example, the horse EDTA blood that was dropped onto the ridgesof the top sheet did not slip down into the furrows but slowly drippedwhile partially remaining on the top sheet, and a portion thereofremained on the ridges.

The following experiment was also conducted in order to confirm thefunction of the blood slipping agent.

Example 3

[Viscosity of Blood Containing Blood Slipping Agent]

The viscosity of the blood slipping agent-containing blood was measuredusing a Rheometric Expansion System ARES (Rheometric Scientific, Inc.).After adding 2 mass % of PANACET 810s to horse defibrinated blood, themixture was gently agitated to form a sample, the sample was placed on a50 mm-diameter parallel plate, with a gap of 100 μm, and the viscositywas measured at 37±0.5° C. The sample was not subjected to a uniformshear rate due to the parallel plate, but the average shear rateindicated by the device was 10 s⁻¹.

The viscosity of the horse defibrinated blood containing 2 mass %PANACET 810s was 5.9 mPa·s, while the viscosity of the horsedefibrinated blood containing no blood slipping agent was 50.4 mPa·s.Thus, the horse defibrinated blood containing 2 mass % PANACET 810sclearly had an approximately 90% lower viscosity than the bloodcontaining no blood slipping agent.

It is known that blood contains components, such as blood cells and hasa thixotropic nature, and it is believed that the blood slipping agentof the present disclosure has an effect of lowering the viscosity ofblood, such as menstrual blood in the low viscosity range. Lowering theblood viscosity presumably allows absorbed menstrual blood to moreeasily migrate rapidly from the top sheet to the absorbent body.

Example 4

[Photomicrograph of Blood Slipping Agent-containing Blood]

Menstrual blood was sampled from healthy volunteers onto thin plasticwrap, and PANACET 810s dispersed in a 10-fold mass of phosphate-bufferedsaline was added to a portion thereof to a PANACET 810s concentration of1 mass %. The menstrual blood was dropped onto a slide glass, a coverglass was placed thereover, and the state of the erythrocytes wasobserved with an optical microscope. A photomicrograph of menstrualblood containing no blood slipping agent is shown in FIG. 8(a), and aphotomicrograph of menstrual blood containing PANACET 810s is shown inFIG. 8(b).

From FIG. 8 it is seen that the erythrocytes formed aggregates, such asrouleaux in the menstrual blood containing no blood slipping agent,while the erythrocytes were stably dispersed in the menstrual bloodcontaining PANACET 810s. This suggests that the blood slipping agentfunctions to stabilize erythrocytes in blood.

Example 5

[Surface Tension of Blood Containing Blood Slipping Agent]

The surface tension of blood containing a blood slipping agent wasmeasured by the pendant drop method, using a Drop Master500 contactangle meter by Kyowa Interface Science Co., Ltd. The surface tension wasmeasured after adding a prescribed amount of blood slipping agent tosheep defibrinated blood, and thoroughly shaking.

The measurement was accomplished automatically with a device, and thesurface tension γ was determined by the following formula (see FIG. 9).γ=g×ρ×(de)²×1/H

g: Gravitational constant

1/H: Correction factor determined from ds/de

ρ: Density

de: Maximum diameter

ds: Diameter at location of increase by de from dropping edge

The density ρ was measured at the temperatures listed in Table 4,according to JIS K 2249-1995, “Density test methods anddensity/mass/volume conversion tables”, “5. Vibrating density testmethod”.

The measurement was accomplished using a DA-505 by Kyoto ElectronicsCo., Ltd.

The results are shown in Table 4 below.

TABLE 4 Blood slipping agent Measuring Surface Amount temperaturetension No. Type (mass %) (° C.) (mN/m) 5-1 — — 35 62.1 5-2 PANACET 0.0135 61.5 5-3 810s 0.05 35 58.2 5-4 0.10 35 51.2 5-5 ELECTOL 0.10 35 58.8WE20 5-6 PARLEAM 0.10 35 57.5 6 5-7 — — 50 56.3 5-8 WILBRITE 0.10 5049.1 cp9

Based on Table 4 it is seen that the blood slipping agent has an effectof lowering the surface tension of blood.

Lowering the surface tension of blood presumably allows absorbed bloodto rapidly migrate from the top sheet to the absorbent body, withoutbeing retained between the top sheet fibers.

The present disclosure relates to the following J1 to J10.

[J1]

An absorbent article comprising a liquid-permeable top sheet, aliquid-impermeable back sheet, and an absorbent body between the topsheet and the back sheet,

wherein the liquid-permeable top sheet has, in an excretory openingcontact region, a blood slipping agent-containing region containing ablood slipping agent with a kinematic viscosity of 0.01 to 80 mm²/s at40° C., a water holding percentage of 0.01 to 4.0 mass % and aweight-average molecular weight of less than 1,000, and

in the blood slipping agent-containing region, the amount of bloodslipping agent on a clothing side surface of the top sheet is greaterthan the amount of blood slipping agent on a skin side surface of thetop sheet at the point of overlap in a thickness direction of theabsorbent article.

[J2]

The absorbent article according to J1, wherein the blood slipping agentfurther has an IOB of 0.00 to 0.60.

[J3]

The absorbent article according to J1 or J2, wherein the absorbentarticle is formed by coating the blood slipping agent or a bloodslipping agent-containing composition containing the blood slippingagent onto a surface of the top sheet on which the clothing side surfaceis to be formed, to form the blood slipping agent-containing region onthe top sheet, and then layering the top sheet, the absorbent body andthe back sheet.

[J4]

The absorbent article according to J1 or J2, wherein the absorbentarticle further includes a second sheet between the top sheet and theabsorbent body, the second sheet includes the blood slippingagent-containing region containing the blood slipping agent, and theamount of blood slipping agent on a skin side surface of the secondsheet is greater than the amount of blood slipping agent on the skinside surface of the top sheet in the blood slipping agent-containingregion at the point of overlap in a thickness direction of the absorbentarticle.

[J5]

The absorbent article according to J4, wherein the absorbent article isformed by coating the blood slipping agent or a blood slippingagent-containing composition containing the blood slipping agent onto asurface of the second sheet on which the skin side surface is to beformed, to form a blood slipping agent-containing region on the secondsheet, and then layering the top sheet, the second sheet, the absorbentbody and the back sheet.

[J6]

The absorbent article according to any one of J1 to J5, wherein theblood slipping agent is selected from the group consisting of followingitems (i) to (iii), and any combination thereof:

(i) a hydrocarbon;

(ii) a compound having (ii-1) a hydrocarbon moiety and (ii-2) one ormore, same or different groups selected from the group consisting ofcarbonyl group (—CO—) and oxy group (—O—) inserted between a C—C singlebond of the hydrocarbon moiety; and

(iii) a compound having (iii-1) a hydrocarbon moiety, (iii-2) one ormore, same or different groups selected from the group consisting ofcarbonyl group (—CO—) and oxy group (—O—), inserted between a C—C singlebond of the hydrocarbon moiety, and (iii-3) one or more, same ordifferent groups selected from the group consisting of carboxyl group(—COOH) and hydroxyl group (—OH), substituting a hydrogen on thehydrocarbon moiety;

with the proviso that when two or more oxy groups are inserted in thecompound of (ii) or (iii), the oxy groups are not adjacent.

[J7]

The absorbent article according to any one of J1 to J6, wherein theblood slipping agent is selected from the group consisting of followingitems (i′) to (iii′), and any combination thereof:

(i′) a hydrocarbon;

(ii′) a compound having (ii′-1) a hydrocarbon moiety, and (ii′-2) one ormore, same or different bonds selected from the group consisting ofcarbonyl bond (—CO—), ester bond (—COO—), carbonate bond (—OCOO—), andether bond (—O—) inserted between a C—C single bond of the hydrocarbonmoiety; and

(iii′) a compound having (iii′-1) a hydrocarbon moiety, (iii′-2) one ormore, same or different bonds selected from the group consisting ofcarbonyl bond (—CO—), ester bond (—COO—), carbonate bond (—OCOO—), andether bond (—O—) inserted between a C—C single bond of the hydrocarbonmoiety, and (iii′-3) one or more, same or different groups selected fromthe group consisting of carboxyl group (—COOH) and hydroxyl group (—OH)substituting a hydrogen on the hydrocarbon moiety;

with the proviso that when two or more same or different bonds areinserted in the compound of (ii′) or (iii′), the bonds are not adjacent.

[J8]

The absorbent article according to any one of J1 to J7, wherein theblood slipping agent is selected from the group consisting of followingitems (A) to (F), as well as any combination thereof:

(A) an ester of (A1) a compound having a chain hydrocarbon moiety and2-4 hydroxyl groups substituting hydrogens on the chain hydrocarbonmoiety, and (A2) a compound having a chain hydrocarbon moiety and onecarboxyl group substituting a hydrogen on the chain hydrocarbon moiety;

(B) an ether of (B1) a compound having a chain hydrocarbon moiety and2-4 hydroxyl groups substituting hydrogens on the chain hydrocarbonmoiety, and (B2) a compound having a chain hydrocarbon moiety and onehydroxyl group substituting a hydrogen on the chain hydrocarbon moiety;

(C) an ester of (C1) a carboxylic acid, hydroxy acid, alkoxy acid oroxoacid containing a chain hydrocarbon moiety and 2-4 carboxyl groupssubstituting hydrogens on the chain hydrocarbon moiety, and (C2) acompound having a chain hydrocarbon moiety and one hydroxyl groupsubstituting a hydrogen on the chain hydrocarbon moiety;

(D) a compound having a chain hydrocarbon moiety, and one bond selectedfrom the group consisting of ether bond (—O—), carbonyl bond (—CO—),ester bond (—COO—) and carbonate bond (—OCOO—), inserted between a C—Csingle bond of the chain hydrocarbon moiety;

(E) a polyoxy C₃-C₆ alkylene glycol, or alkyl ester or alkyl etherthereof; and

(F) a chain hydrocarbon.

[J9]

The absorbent article according to any one of J1 to J8, wherein theblood slipping agent is selected from the group consisting of (a₁) anester of a chain hydrocarbon tetraol and at least one fatty acid, (a₂)an ester of a chain hydrocarbon triol and at least one fatty acid, (a₃)an ester of a chain hydrocarbon diol and at least one fatty acid, (b₁)an ether of a chain hydrocarbon tetraol and at least one aliphaticmonohydric alcohol, (b₂) an ether of a chain hydrocarbon triol and atleast one aliphatic monohydric alcohol, (b₃) an ether of a chainhydrocarbon diol and at least one aliphatic monohydric alcohol, (c₁) anester of a chain hydrocarbon tetracarboxylic acid, hydroxy acid, alkoxyacid or oxoacid with 4 carboxyl groups, and at least one aliphaticmonohydric alcohol, (c₂) an ester of a chain hydrocarbon tricarboxylicacid, hydroxy acid, alkoxy acid or oxoacid with 3 carboxyl groups, andat least one aliphatic monohydric alcohol, (c₃) an ester of a chainhydrocarbon dicarboxylic acid, hydroxy acid, alkoxy acid or oxoacid with2 carboxyl groups, and at least one aliphatic monohydric alcohol, (d₁)an ether of an aliphatic monohydric alcohol and an aliphatic monohydricalcohol, (d₂) a dialkyl ketone, (d₃) an ester of a fatty acid and analiphatic monohydric alcohol, (d₄) a dialkyl carbonate, (e₁) a polyoxyC₃-C₆ alkylene glycol, (e₂) an ester of a polyoxy C₃-C₆ alkylene glycoland at least one fatty acid, (e₃) an ether of a polyoxy C₃-C₆ alkyleneglycol and at least one aliphatic monohydric alcohol, and (f₁) a chainalkane, as well as any combination thereof.

[J10]

The absorbent article according to any one of J1 to J9, wherein the topsheet and second sheet are each selected from the group consisting ofnonwoven fabrics, woven fabrics and porous films, and in the bloodslipping agent-containing region, the blood slipping agent adheres asdroplets or particulates on the surfaces of the fibers of the nonwovenfabric or woven fabric, or the surface of the porous film.

[J11]

The absorbent article according to any one of J1 to J10, wherein theabsorbent article is a sanitary napkin or panty liner.

[J12]

A method of producing an absorbent article having a liquid-permeable topsheet, a liquid-impermeable back sheet, and an absorbent body betweenthe liquid-permeable top sheet and liquid-impermeable back sheet,comprising the steps of:

coating a surface of the top sheet on which a clothing side surface isto be formed, with a blood slipping agent having a kinematic viscosityof 0.01 to 80 mm²/s at 40° C., a water holding percentage of 0.01 to 4.0mass % and a weight-average molecular weight of less than 1,000, or ablood slipping agent-containing composition containing the bloodslipping agent, to form a blood slipping agent-containing region in anexcretory opening contact region; and

layering the absorbent body and the back sheet on the surface of the topsheet on which the clothing side surface is to be formed, to form theabsorbent article;

wherein in the blood slipping agent-containing region, the amount ofblood slipping agent on the clothing side surface of the top sheet isgreater than the amount of blood slipping agent on a skin side surfaceof the top sheet.

[J13]

A method of producing an absorbent article having a liquid-permeable topsheet, an absorbent body, a liquid-impermeable back sheet, and a secondsheet between the top sheet and the absorbent body, comprising the stepsof:

coating a surface of the second sheet on which a skin side surface is tobe formed, with a blood slipping agent having a kinematic viscosity of0.01 to 80 mm²/s at 40° C., a water holding percentage of 0.01 to 4.0mass % and a weight-average molecular weight of less than 1,000, or ablood slipping agent-containing composition containing the bloodslipping agent, to form a blood slipping agent-containing region in anexcretory opening contact region; and

layering the top sheet on the surface of the second sheet on which theskin side surface is to be formed, and layering the absorbent body andthe back sheet on a surface of the second sheet on which a clothing sidesurface is to be formed, to form the absorbent article;

wherein in the blood slipping agent-containing region, the amount ofblood slipping agent on a clothing side surface of the top sheet isgreater than the amount of blood slipping agent on a skin side surfaceof the top sheet, and in the blood slipping agent-containing region, theamount of blood slipping agent on the skin side surface of the secondsheet is greater than the amount of blood slipping agent on the skinside surface of the top sheet.

REFERENCES SIGNS LIST

-   1 Absorbent article-   2 Top sheet-   3 Absorbent body-   4 Side flap-   5 Side sheet-   6 Embossing-   7 Blood slipping agent-containing region-   8 Back sheet-   9 Blood slipping agent-   10 Skin side surface-   11 Clothing side surface-   12 Second sheet-   21 Projection-   22 Recess-   23, 23′, 23″ Menstrual blood

The invention claimed is:
 1. An absorbent article comprising aliquid-permeable top sheet, a liquid-impermeable back sheet, and anabsorbent body between the top sheet and the back sheet, wherein theliquid-permeable top sheet has, in an excretory opening contact region,a blood slipping agent-containing region containing a blood slippingagent with a kinematic viscosity of 0.01 to 80 mm²/s at 40° C., a waterholding percentage of 0.01 to 4.0 mass % and a weight-average molecularweight of less than 1,000, and in the blood slipping agent-containingregion, the amount of blood slipping agent on a clothing side surface ofthe top sheet is greater than the amount of blood slipping agent on askin side surface of the top sheet at the point of overlap in athickness direction of the absorbent article.
 2. The absorbent articleaccording to claim 1, wherein the blood slipping agent further has aninorganic organic balance (IOB) of 0.00 to 0.60.
 3. The absorbentarticle according to claim 1, wherein the absorbent article is formed bycoating the blood slipping agent or a blood slipping agent-containingcomposition containing the blood slipping agent onto a surface of thetop sheet on which the clothing side surface is to be formed, to formthe blood slipping agent-containing region on the top sheet, and thenlayering the top sheet, the absorbent body and the back sheet.
 4. Theabsorbent article according to claim 1, wherein the absorbent articlefurther includes a second sheet between the top sheet and the absorbentbody, the second sheet includes the blood slipping agent-containingregion containing the blood slipping agent, and the amount of bloodslipping agent on a skin side surface of the second sheet is greaterthan the amount of blood slipping agent on the skin side surface of thetop sheet in the blood slipping agent-containing region at the point ofoverlap in a thickness direction of the absorbent article.
 5. Theabsorbent article according to claim 4, wherein the absorbent article isformed by coating the blood slipping agent or a blood slippingagent-containing composition containing the blood slipping agent onto asurface of the second sheet on which the skin side surface is to beformed, to form a blood slipping agent-containing region on the secondsheet, and then layering the top sheet, the second sheet, the absorbentbody and the back sheet.
 6. The absorbent article according to claim 1,wherein the blood slipping agent is selected from the group consistingof: (i) a hydrocarbon; (ii) a compound having (ii-1) a hydrocarbonmoiety and (ii-2) one or more, same or different groups selected fromthe group consisting of carbonyl group (—CO—) and oxy group (—O—)inserted between a C—C single bond of the hydrocarbon moiety; and (iii)a compound having (iii-1) a hydrocarbon moiety, (iii-2) one or more,same or different groups selected from the group consisting of carbonylgroup (—CO—) and oxy group (—O—), inserted between a C—C single bond ofthe hydrocarbon moiety, and (iii-3) one or more, same or differentgroups selected from the group consisting of carboxyl group (—COON) andhydroxyl group (—OH), substituting a hydrogen on the hydrocarbon moiety;and (iv) any combination thereof; with the proviso that when two or moreoxy groups are inserted in the compound of (ii) or (iii), the oxy groupsare not adjacent.
 7. The absorbent article according to claim 1, whereinthe blood slipping agent is selected from the group consisting of: (i′)a hydrocarbon; (ii′) a compound having (ii′-1) a hydrocarbon moiety, and(ii′-2) one or more, same or different bonds selected from the groupconsisting of carbonyl bond (—CO—), ester bond (—COO—), carbonate bond(—OCOO—), and ether bond (—O—) inserted between a C—C single bond of thehydrocarbon moiety; and (iii′) a compound having (iii′-1) a hydrocarbonmoiety, (iii′-2) one or more, same or different bonds selected from thegroup consisting of carbonyl bond (—CO—), ester bond (—COO—), carbonatebond (—OCOO—), and ether bond (—O—) inserted between a C—C single bondof the hydrocarbon moiety, and (iii′-3) one or more, same or differentgroups selected from the group consisting of carboxyl group (—COON) andhydroxyl group (—OH) substituting a hydrogen on the hydrocarbon moiety;and (iv′) any combination thereof; with the proviso that when two ormore same or different bonds are inserted in the compound of (ii′) or(iii′), the bonds are not adjacent.
 8. The absorbent article accordingto claim 1, wherein the blood slipping agent is selected from the groupconsisting of: (A) an ester of (A1) a compound having a chainhydrocarbon moiety and 2-4 hydroxyl groups substituting hydrogens on thechain hydrocarbon moiety, and (A2) a compound having a chain hydrocarbonmoiety and one carboxyl group substituting a hydrogen on the chainhydrocarbon moiety; (B) an ether of (B1) a compound having a chainhydrocarbon moiety and 2-4 hydroxyl groups substituting hydrogens on thechain hydrocarbon moiety, and (B2) a compound having a chain hydrocarbonmoiety and one hydroxyl group substituting a hydrogen on the chainhydrocarbon moiety; (C) an ester of (C1) a carboxylic acid, hydroxyacid, alkoxy acid or oxoacid containing a chain hydrocarbon moiety and2-4 carboxyl groups substituting hydrogens on the chain hydrocarbonmoiety, and (C2) a compound having a chain hydrocarbon moiety and onehydroxyl group substituting a hydrogen on the chain hydrocarbon moiety;(D) a compound having a chain hydrocarbon moiety, and one bond selectedfrom the group consisting of ether bond (—O—), carbonyl bond (—CO—),ester bond (—COO—) and carbonate bond (—OCOO—), inserted between a C—Csingle bond of the chain hydrocarbon moiety; (E) a polyoxy C₃-C₆alkylene glycol, or alkyl ester or alkyl ether thereof; and (F) a chainhydrocarbon; and (G) any combination thereof.
 9. The absorbent articleaccording to claim 1, wherein the blood slipping agent is selected fromthe group consisting of (a₁) an ester of a chain hydrocarbon tetraol andat least one fatty acid, (a₂) an ester of a chain hydrocarbon triol andat least one fatty acid, (a₃) an ester of a chain hydrocarbon diol andat least one fatty acid, (b₁) an ether of a chain hydrocarbon tetraoland at least one aliphatic monohydric alcohol, (b₂) an ether of a chainhydrocarbon triol and at least one aliphatic monohydric alcohol, (b₃) anether of a chain hydrocarbon diol and at least one aliphatic monohydricalcohol, (c₁) an ester of a chain hydrocarbon tetracarboxylic acid,hydroxy acid, alkoxy acid or oxoacid with 4 carboxyl groups, and atleast one aliphatic monohydric alcohol, (c₂) an ester of a chainhydrocarbon tricarboxylic acid, hydroxy acid, alkoxy acid or oxoacidwith 3 carboxyl groups, and at least one aliphatic monohydric alcohol,(c₃) an ester of a chain hydrocarbon dicarboxylic acid, hydroxy acid,alkoxy acid or oxoacid with 2 carboxyl groups, and at least onealiphatic monohydric alcohol, (d₁) an ether of an aliphatic monohydricalcohol and an aliphatic monohydric alcohol, (d₂) a dialkyl ketone, (d₃)an ester of a fatty acid and an aliphatic monohydric alcohol, (d₄) adialkyl carbonate, (e₁) a polyoxy C₃-C₆ alkylene glycol, (e₂) an esterof a polyoxy C₃-C₆ alkylene glycol and at least one fatty acid, (e₃) anether of a polyoxy C₃-C₆ alkylene glycol and at least one aliphaticmonohydric alcohol, and (f₁) a chain alkane, as well as any combinationthereof.
 10. The absorbent article according to claim 1, wherein the topsheet and second sheet are each selected from the group consisting ofnonwoven fabrics, woven fabrics and porous films, and in the bloodslipping agent-containing region, the blood slipping agent adheres asdroplets or particulates on the surfaces of the fibers of the nonwovenfabric or woven fabric, or the surface of the porous film.
 11. Theabsorbent article according to claim 1, wherein the absorbent article isa sanitary napkin or panty liner.
 12. A method of producing an absorbentarticle having a liquid-permeable top sheet, a liquid-impermeable backsheet, and an absorbent body between the liquid-permeable top sheet andliquid-impermeable back sheet, comprising the steps of: coating asurface of the top sheet on which a clothing side surface is to beformed, with a blood slipping agent having a kinematic viscosity of 0.01to 80 mm²/s at 40° C., a water holding percentage of 0.01 to 4.0 mass %and a weight-average molecular weight of less than 1,000, or a bloodslipping agent-containing composition containing the blood slippingagent, to form a blood slipping agent-containing region in an excretoryopening contact region; and layering the absorbent body and the backsheet on the surface of the top sheet on which the clothing side surfaceis to be formed, to form the absorbent article; wherein in the bloodslipping agent-containing region, the amount of blood slipping agent onthe clothing side surface of the top sheet is greater than the amount ofblood slipping agent on a skin side surface of the top sheet.
 13. Amethod of producing an absorbent article having a liquid-permeable topsheet, an absorbent body, a liquid-impermeable back sheet, and a secondsheet between the top sheet and the absorbent body, comprising the stepsof: coating a surface of the second sheet on which a skin side surfaceis to be formed, with a blood slipping agent having a kinematicviscosity of 0.01 to 80 mm²/s at 40° C., a water holding percentage of0.01 to 4.0 mass % and a weight-average molecular weight of less than1,000, or a blood slipping agent-containing composition containing theblood slipping agent, to form a blood slipping agent-containing regionin an excretory opening contact region; and layering the top sheet onthe surface of the second sheet on which the skin side surface is to beformed, and layering the absorbent body and the back sheet on a surfaceof the second sheet on which a clothing side surface is to be formed, toform the absorbent article; wherein in the blood slippingagent-containing region, the amount of blood slipping agent on aclothing side surface of the top sheet is greater than the amount ofblood slipping agent on a skin side surface of the top sheet, and in theblood slipping agent-containing region, the amount of blood slippingagent on the skin side surface of the second sheet is greater than theamount of blood slipping agent on the skin side surface of the topsheet.